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Abstract: This paper presents an evolutionary algorithm for wind speed reconstruction from synoptic pressure patterns. The algorithm operates in a search space formed by grids of pressure measures, and must classify the different situations into classes, in such a way that a measure of wind speed in a given point is minimized among patterns assigned to the same class. Then, each class is assigned a mean wind speed and direction, so the wind speed reconstruction is possible for a new grid of synoptic pressures. In this paper we present the problem model and the specific description of the evolutionary algorithm proposed to solve the problem. We also show the good performance of the proposed method in the reconstruction of the average wind speed in six wind towers in Spain. The proposed method is applicable to wind speed reconstruction or reconstruction of wind missing data of wind series, specially when there is no other variable or related measure available. [Copyright &y& Elsevier]

Abstract: In this paper the inventory of 90Sr in 34 points distributed along the Spanish peninsular territory is presented. Obtained values range between 173 Bq/m2 and 2047 Bq/m2. From these data set and those 137Cs data obtained in a previous work the 137Cs/90Sr activity ratio has been established, laying this value between 0.9 and 3.6. Also the migration depth of both radionuclides has been analysed obtaining for 137Cs an average value 57% lower than that obtained for 90Sr. Additionally, this paper presents the results obtained in 11 sampling points in which the activity vertical profile has been measured. These profiles have been analysed to state the behaviour of strontium in soils and after, by using a convective–diffusive model, the parameters of the model which governs the vertical migration of 90Sr in the soil, v (apparent convection velocity) and D (apparent diffusion coefficient) have been evaluated. Mean values obtained are 0.20 cm/year and 3.67 cm2/year, respectively. [Copyright &y& Elsevier]

Abstract: In recent years, fuzzy models have been acknowledged as a suitable approach for species distribution modelling due to their transparency and their ability to incorporate the ecological gradient theory. Specifically, the overlapping class boundaries of a fuzzy model are similar to the transitions between different environmental conditions. However, the need for ecological expert knowledge is an important constraint when applying fuzzy species distribution models. Moreover, the consistency of the ecological preferences of some fish species across different rivers has been widely contested. Recent research has shown that data-driven fuzzy models may solve this ‘knowledge acquisition bottleneck’ and this paper is a further contribution. The aim was to analyse the brown trout (Salmo trutta fario L.) habitat preferences based on a data-driven fuzzy modelling technique and to compare the resulting fuzzy models with a commonly applied modelling technique, Random Forests. A heuristic nearest ascent hill-climbing algorithm for fuzzy rule optimisation and Random Forests were applied to analyse the ecological preferences of brown trout in 93 mesohabitats. No significant differences in model performance were observed between the optimal fuzzy model and the Random Forests model and both approaches selected river width, the cover index and flow velocity as the most important variables describing brown trout habitat suitability. Further, the fuzzy model combined ecological relevance with reasonable interpretability, whereas the transparency of the Random Forests model was limited. This paper shows that fuzzy models may be a valid approach for species distribution modelling and that their performance is comparable to that of state-of-the-art modelling techniques like Random Forests. Fuzzy models could therefore be a valuable decision support tool for river managers and enhance communication between stakeholders. [Copyright &y& Elsevier]

Abstract: This paper proposes the use of a new Measure–Correlate–Predict (MCP) method to estimate the long-term wind speed characteristics at a potential wind energy conversion site. The proposed method uses the probability density function of the wind speed at a candidate site conditioned to the wind speed at a reference site. Contingency-type bivariate distributions with specified marginal distributions are used for this purpose. The proposed model was applied in this paper to wind speeds recorded at six weather stations located in the Canary Islands (Spain). The conclusion reached is that the method presented in this paper, in the majority of cases, provides better results than those obtained with other MCP methods used for purposes of comparison. The metrics employed in the analysis were the coefficient of determination (R 2) and the root relative squared error (RRSE). The characteristics that were analysed were the capacity of the model to estimate the long-term wind speed probability distribution function, the long-term wind power density probability distribution function and the long-term wind turbine power output probability distribution function at the candidate site. [Copyright &y& Elsevier]

Abstract: The control of accidents at the work place is a critical issue all over the world. The consequences of occupational accidents in terms of costs for the company in which the accidents take place is only one minor matter, being the social impact and the loss of human life the most controversial effects of this important problem. The methods used to forecast future evolution of accidents are often limited to trend estimations and projections, being the scientific literature on this topic rather scarce. This paper aims at showing and predicting the evolution of Spanish occupational accidents of different levels of severity, allowing the evaluation of the influence that preventive actions carried out by public administrations or private companies may have over the number of occupational accidents. Though some contributions may be found on this topic for Spain, this paper is the first contribution that forecast occupational accidents for different levels of severity using Multivariate Unobserved Components models developed in a State Space framework extended to deal with the irregular sampling interval of the data. Data from 1998 to 2009 have been used to test the efficacy of the forecasting system. [ABSTRACT FROM AUTHOR]

In this paper, we propose a method for finding the optimal route for a specific train from a station to another one in the Spanish railway network (or any railway network involving different incompatible features like gauges, electrification and signaling systems). The complexity of the Spanish railway infrastructure makes it difficult to give an estimation of the fastest route of a train from a given station to another. Indeed, very unintuitive situations may happen. The problem of finding fastest routes is typically modeled by a graph where nodes represent stations and edges represent railway sections. However, this approach is not suitable for the Spanish railway network. In order to solve the problem of calculating the fastest routes, we will propose here a novel approach based on modeling the railway network through a different graph whose nodes represent railway sections. [ABSTRACT FROM AUTHOR]

Computational thinking (CT) is being located at the focus of educational innovation, as a set of problem-solving skills that must be acquired by the new generations of students to thrive in a digital world full of objects driven by software. However, there is still no consensus on a CT definition or how to measure it. In response, we attempt to address both issues from a psychometric approach. On the one hand, a Computational Thinking Test (CTt) is administered on a sample of 1,251 Spanish students from 5th to 10th grade, so its descriptive statistics and reliability are reported in this paper. On the second hand, the criterion validity of the CTt is studied with respect to other standardized psychological tests: the Primary Mental Abilities (PMA) battery, and the RP30 problem-solving test. Thus, it is intended to provide a new instrument for CT measurement and additionally give evidence of the nature of CT through its associations with key related psychological constructs. Results show statistically significant correlations at least moderately intense between CT and: spatial ability ( r = 0.44), reasoning ability ( r = 0.44), and problem-solving ability ( r = 0.67). These results are consistent with recent theoretical proposals linking CT to some components of the Cattel-Horn-Carroll (CHC) model of intelligence, and corroborate the conceptualization of CT as a problem-solving ability. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study conducted in the University of Salamanca, on the behavioral intention of using mobile devices within the future teaching practice of pre-service primary education teachers. To this end we elaborated a technology adoption model based on the Technology Acceptance Model (TAM), to which we incorporated the constructs of self-efficacy and mobile anxiety. The study consisted of 678 participants from the Primary Education Teacher Bachelor's Degree at said university. The model was examined with the PLS-SEM technique. The analysis supported all the relational hypotheses proposed, and suggested that the stronger relationships were those established between perceived usefulness and behavioral intention, perceived ease of use and perceived usefulness, and self-efficacy and perceived ease of use. The multi-group analysis barely yielded any significant differences at a structural level controlling for gender and course year. However, we did find some significant differences between mean scores at an indicator level. The PLS-POS analysis of unobserved heterogeneity identified two groups with significant differences in their path coefficients. [ABSTRACT FROM AUTHOR]

The paper presents an integrated approach aimed at assessing the seismic safety of Mallorca cathedral. This cathedral is an extraordinary historical construction dating back to the middle-ages. The experimental modal parameters of the cathedral were identified using Ambient Vibration Testing (AVT). The cathedral numerical model was updated using the identified modal parameters. This updated model was then used to study the seismic response of the cathedral using non-linear static (pushover) analysis. A sensitively analysis was carried out to reveal the dependency of the seismic capacity on the input materials properties. To assess the seismic performance and the safety of the cathedral, the N2 method was employed. It was found that the cathedral is safe when subjected to the earthquakes expected in Mallorca Island. [ABSTRACT FROM AUTHOR]

The Spanish residential building stock built between 1940 and 1980 period presents a high energy saving potential as it represents a significant percentage of the total housing stock and it was built without any regulation regarding energy efficiency. Accordingly, the first aim of this paper was to quantify the energy saving potential and the related reduction in CO 2 emissions of the housing stock in those years. The work focuses on the Mediterranean climate of the Comunitat Valenciana Region, therefore the energy efficiency strategies proposed are passive and deal with the envelope of buildings. On the basis of the results obtained, several scenarios with intervention periods of 10, 20 and 30 years were calculated. The conclusion was that with the current rate of annual building renovation, it will be nearly impossible to reach the goals established by the EPBD. Only a deep transformation of the building fabric within this sector could help in achieving them. Finally, it should be noted that the proposed methodology can be applied to other areas with different climates, particularly in Spain. [ABSTRACT FROM AUTHOR]

Solar radiation estimates with clear sky models require estimations of aerosol data. The low spatial resolution of current aerosol datasets, with their remarkable drift from measured data, poses a problem in solar resource estimation. This paper proposes a new downscaling methodology by combining support vector machines for regression (SVR) and kriging with external drift, with data from the MACC reanalysis datasets and temperature and rainfall measurements from 213 meteorological stations in continental Spain. The SVR technique was proven efficient in aerosol variable modeling. The Linke turbidity factor (TL) and the aerosol optical depth at 550 nm (AOD 550) estimated with SVR generated significantly lower errors in AERONET positions than MACC reanalysis estimates. The TL was estimated with relative mean absolute error (rMAE) of 10.2% (compared with AERONET), against the MACC rMAE of 18.5%. A similar behavior was seen with AOD 550, estimated with rMAE of 8.6% (compared with AERONET), against the MACC rMAE of 65.6%. Kriging using MACC data as an external drift was found useful in generating high resolution maps (0.05° × 0.05°) of both aerosol variables. We created high resolution maps of aerosol variables in continental Spain for the year 2008. The proposed methodology was proven to be a valuable tool to create high resolution maps of aerosol variables (TL and AOD 550). This methodology shows meaningful improvements when compared with estimated available databases and therefore, leads to more accurate solar resource estimations. This methodology could also be applied to the prediction of other atmospheric variables, whose datasets are of low resolution. [ABSTRACT FROM AUTHOR]

Abstract: Benzo(a)pyrene (BaP) is one of the most dangerous PAH due to its high carcinogenic and mutagenic character. Because of this reason, the Directive 2004/107/CE of the European Union establishes a target value of 1 ng/m3 of BaP in the atmosphere. In this paper, the main aim is to estimate the BaP concentrations in the atmosphere by using last generation of air quality dispersion models with the inclusion of the transport, scavenging and deposition processes for the BaP. The degradation of the particulated BaP by the ozone has been considered. The aerosol–gas partitioning phenomenon in the atmosphere is modelled taking into a count that the concentrations in the gas and the aerosol phases. If the pre-existing organic aerosol concentrations are zero gas/particle equilibrium is established. The model has been validated at local scale with data from a sampling campaign carried out in the area of Zaragoza (Spain) during 12 weeks. [Copyright &y& Elsevier]

Abstract: Many organizations are implementing process improvement models, seeking to increase their organizational maturity for software development. However, implementing traditional maturity models involves a large investment (as regards money, time and resources) which is beyond the reach of vast majority of small organizations. This paper presents the use and adaptation of some ISO models in the creation of an organizational maturity model for the Spanish software industry. This model was used satisfactorily to (i) improve the software processes of several Spanish small firms, and (ii) obtain an organizational maturity certification for software development, granted by the Spanish Association for Standardization and Certification. [Copyright &y& Elsevier]

Abstract: In a number of countries where large penetration of wind generation has been developed, the increased impact of wind energy generation on power grid operations has led to the development of grid codes, with the aim of integrating this source of energy without compromising the stability of their networks. In Spain this grid code is named the Procedure of Operation for fault ride-through capability of the Spanish national grid code —PO 12.3—. To verify the fulfillment of this grid code, it has also been defined a procedure for measuring and evaluating the response of wind turbines and wind farms submitted to voltage dips —Procedure for verification, validation and certification of the requirements of the PO 12.3 on the response of wind farms in the event of voltage dips (PVVC)—. In this paper, two-phase voltage dips that comply with the requirements of the PVVC, has been applied to a Gamesa G52 with a Dip Active Converter. The measured tests are compared with the simulation of a PSCAD model of the wind turbine to verify the fulfillment of the PVVC validation process and the results obtained are presented. [Copyright &y& Elsevier]

Abstract: Evidence shows that divorces are related to the economy and social contagion, as well as to the existence of a difference in happiness between the couple. This paper deals with the mathematical modeling of divorce propagation allowing the estimation of the future divorced population. We use a coupled discrete linear-quadratic difference system model and data collected from the Spanish Statistics Institute (INE). A sensitivity analysis of the growth of the divorced population with respect to the contagion rate is included, and several different economic scenarios are considered. [Copyright &y& Elsevier]

Abstract: Anxiolytics (AX) are the psychotropic drugs prescribed for the treatment of anxiety and insomnia for 2–4 weeks, for longer periods of consumption (>1 month) may lead to the development of tolerance or addiction. In fact, its prescription was 16% of the total pharmaceutical expenditure in Spain in 2007. This paper deals with the development of a mathematical model describing the dynamic of the addiction to AX for the case study of the Spanish region of Castellón. The reasons believed to cause the development of addicts to AX are the economic situation, the marriage termination and the social contact. The simulations performed to forecast the addicts rate for the period 2010–2014 showed an increase from 6% in 2010 to 14% in 2014 with a fluctuation of about 2% between the possible economic scenarios. Finally, the analysis of sensitivity of the rate of addicts to the fluctuation of the social contact parameters was performed, letting us estimate its impact on the pharmaceutical expenditure. [Copyright &y& Elsevier]

Abstract: Many studies have attempted to measure human response in music halls in order to determine acoustic quality. However, all these works have used parameters defined by experts. This approach may be an important drawback since users who have to evaluate such concepts may not understand or misunderstand parameters which do not correspond to their own conceptual structure. This paper attempts to establish a methodology to define valid evaluation scales for different collectives and determine evaluation criteria related to the overall assessment of music hall acoustics. It analyses music hall acoustics from the user''s perspective and investigates the differences of perception between experts and non-experts through Semantic Differential within the frame of Kansei Engineering. The research was carried out through a field study in 17 auditoria of the Valencia Region (Spain). Perceptions regarding the acoustic quality of these venues were studied in a group of non-experts (236) and other of experts (74). Differences of perception between both collectives were identified and analysed. The main factors characterising the subjective preference of each group were determined (5 factors for non-experts and 6 for experts) and their influence on the global acoustic assessment was quantified. Furthermore, predicting perceptual models were built and the utility of the methodology was tested through the semantic profiles of two venues not included in the above analysis. This methodology was useful for studying music hall acoustics from the viewpoints of experts and non-experts and it may also enable optimization of design features of music halls. [Copyright &y& Elsevier]

Abstract: The solar updraft power plant system (SUPPS) is a novel kind of solar thermal application, which uses the fluid buoyancy of the chimney effect to achieve output power. To investigate the impact of a strong ambient crosswind on the system output power through the collector inlet and chimney outlet, numerical analysis on the performances of a SUPPS identical to the prototype in Manzanares, Spain which is exposed to the external crosswind with different velocities is carried out in this paper. A geometrical model including the SUPPS and its outside ambience is built and the mathematical models to describe the fluid flow, heat transfer and output power of the whole system are further developed. The pressure, temperature and velocity distribution of the air in the ambience and SUPPS together with the output power of the SUPPS are analyzed. The numerical simulation results reveal that ambient crosswind has influence on the performance of the SUPPS in two ways. On one hand, when the ambient crosswind is comparably weak, it will deteriorate the flow field and reduce the output power of the SUPPS. On the other hand, it may even increase the mass flow rate and output power if the crosswind is strong enough. [Copyright &y& Elsevier]

Abstract: In this paper, we present an extension to the mixed-model sequencing problem with work overload minimisation (MMSP-W) for production lines with serial workstations and parallel homogeneous processors. The extension is intended to meet the industrial need to sequence various products so that the work required and completed at the workstations over time is as constant as possible. Several approaches are proposed to formulate the problem, giving rise to different models. Four models are selected, and their performances are compared after running the Gurobi solver, using instances from the literature and a case study of the Nissan powertrain plant in Barcelona. [Copyright &y& Elsevier]

Abstract: The capacity expansion planning problem of the renewable energy industry involves decisions regarding the optimal mix of different plant types, locations where each plant should be built, and capacity expansion decisions over the planning horizon for each plant. The aim of this paper is to develop a goal programming model, based on a multi-source multi-sink network, in order to locate five renewable energy plants for electric generation in five places located in the autonomous region of Cantabria, in the north of Spain. As different types of plants can be placed in each location, the goal is to locate one plant in each place, maximizing the number of plants that are matched with comparable locations, in a way that the total deviations from goals are minimized. [Copyright &y& Elsevier]

Abstract: Sustainable tourism is being consolidated at an international level as an approach that should be used to make all types of tourism more environmentally, socially and economically beneficial. A common practice is to use an indicator system for designing and implementing tourism models that focuses on the sustainability approach. Indicators are considered as useful tools that allow tourism managers to diagnose the situation of the destination, and to identify and evaluate issues that require addressing to improve the level of sustainability of the tourist activities. However, these indicator systems usually do not provide a practical guide to establish how to interpret information and how to integrate it into the decision-making. In this paper we present an indicator system to evaluate sustainable tourism at cultural destinations. Likewise, we suggest a method based on goal programming to construct composite indicators. The definition of the indicator system and composite indicators is completed providing guidelines that establish how to use these tools in tourism sector planning. Specifically, we propose three basic practical uses for these tools: the formulation of general action plans at a regional level, the definition of short-term strategies for destinations and the establishment of destination benchmarking practices. Each practical use is illustrated using the case of cultural tourism destinations in the Andalusia region (Spain). [Copyright &y& Elsevier]

Abstract: The present work shows the application of a new methodology, to find out the free surface inside earth fill dams under steady flow conditions, to a real field case: the Gasset Dam, in Ciudad Real, Spain. An accurate and fast computation of the free surface is of paramount importance, since it is a previous and necessary step for evaluating the safety of an earth dam in terms of its stress–strain behavior. This new methodology is based on a coupled numerical model formulated in terms of displacements (so called u–w formulation) instead of a more usual approach of water heads. The developed general code has been previously validated using several theoretical seepage problems through porous media. The selected field case is an earth dam built a century ago, which has been subjected to several rehabilitation works since then. Hence, it is a very irregular and nonhomogeneous dam. The comparison of computations and real field measurements, in terms of the free surface location and the total discharge through the dam under steady conditions, is presented in this paper, demonstrating the accuracy and applicability of this formulation to this kind of problems. [Copyright &y& Elsevier]

Abstract: This paper presents a regression analysis of energy consumption in the banking sector. In our case study, the target area is the Spanish banking sector, for which we divide the available data into a prediction and a validation subset. Power models were developed using test data from 55 banks. From the analysis, three models were obtained; where the first proposed model can be used to predict the energy consumption of the whole banking sector, while the rest of the models estimate the energy consumption for branches with low winter climate severity (Model 2) and high winter climate severity (Model 3). Models 2 and 3 differ from the first model in that they need independent variables measured in situ. As a result, the uncertainty of the response variable in the function of the independent variables is reduced by 56.8% for the first model and by 65.2% and 68.5% for the second and third proposed models, respectively. The validation of the first model, which is the model with the lowest determination coefficient, shows that this model is appropriate for predicting the energy consumption of bank branches with good energy consumption performance and detecting inefficiencies in bank branches with poor energy consumption performance. [Copyright &y& Elsevier]

Abstract: With the re-emergence of insurgency tied to terrorism, governments need to strategically manage their communications. This paper analyzes the effect of the Spanish government''s messaging in the face of the Madrid bombing of March 11, 2004: unlike what happened with the 9/11 bombings in the USA and the 7/07 London attacks, the Spanish media did not support the government''s framing of the events. Taking framing as a strategic action in a discursive form (), and in the context of the attribution theory of responsibilities, this research uses the “cascading activation” model () to explore how a framing contest was generated in the press. Analysis of the coverage shows that the intended government frame triggered a battle among the different major newspapers, leading editorials to shift their frame over the four days prior to the national elections. This research analyzes strategic contests in framing processes and contributes insight into the interactions among the different sides (government, parties, media, and citizens) to help bring about an understanding of the rebuttal effect of the government''s intended frame. It also helps to develop an understanding of the role of the media and the influence of citizens’ frames on media content. [Copyright &y& Elsevier]

Abstract: This paper examines the willingness-to-pay of people living in a number of villages in Navarre, in the Spanish Pyrenees to reduce noise and air pollution. Several models are used for estimation based on contingent valuation, noting that those living near roads are willing to pay more to reduce air and noise pollution. In addition, younger people, the better educated, and the more environmentally aware individuals are also willing to pay more to reduce those externalities. [Copyright &y& Elsevier]

Abstract: This paper explores the relationship between tourism and traffic congestion and hyper-congestion using the case study of Mallorca (Spain), one of the most important resort destinations in the Mediterranean. After discussing different proxies to capture the associated problems to road traffic congestion, different time series models are estimated including considering the days of the week, holidays and meteorological determinants jointly with a daily indicator of tourist population pressure. Results show how the tourist pressure variable is an important determinant in explaining the different alternative indicators of traffic congestion and hyper-congestion, for different roads. Hence it is possible to classify the roads in terms of usage by tourists in order to anticipate the levels of traffic intensity, especially during peak periods. [Copyright &y& Elsevier]

Abstract: This paper explains the process followed to generate the model used as a decision support tool for agricultural production planning in the most agrarian areas in Galicia (NW Spain). The model comprises three procedures that use 44 social, environmental and economic indicators developed using both monographic information and field data. The indicators allow for the selection of the most suitable crops and land uses for each agrarian area, and allow decision makers to define key factors for performing a diagnostic analysis and proposing relevant actions regarding agricultural production planning. The potential of the tool for defining a hierarchy of potential crops and land uses according to their degree of suitability has been illustrated by applying the model to one of the 88 Ecological and Economic Units studied (EEUs). The proposed model can be a useful tool for production managers, agricultural associations, governmental agencies and even non-governmental organizations in underdeveloped countries. The most innovative aspects of the model are the feasibility of grouping indicators to perform a diagnostic analysis of different scenarios, and that it can be adapted to any other region in the world, by adjusting the objectives of agricultural production planning and the corresponding indicators. [Copyright &y& Elsevier]

Abstract: The implementation of urban sustainability practices is affected by political obstacles, and diverse political ideologies may defend different city models. Sustainable policy design could also be affected by several factors that cause the deflection of resources initially allocated to other groups that are contrary to the concerns pursued and have the power to veto sustainable plans by exerting pressure on the party in power. In this sense, the aim of this paper is to show the impact that political factors have on cities’ sustainability, and the effect of both on cities’ economic development. To do so, we used the 78 Spanish cities with a population over 100,000 studied by MERCO (Spanish Corporate Reputation Monitor) as regards their levels of sustainability for the fiscal years 2008 and 2009. Both relationships have been tested empirically through two dependence models using linear regression techniques. The results obtained show that political competition improves cities’ sustainability, while a leftist ideology has an inverse impact. On the other hand, a significant direct relationship has been observed between urban sustainability and municipal economic activity. [Copyright &y& Elsevier]

Abstract: Competitive structure of power markets causes various challenges for wind resources to participate in these markets. Indeed, production uncertainty is the main cause of their low income. Thus, they are usually supported by system operators, which is in contrast with the competitive paradigm of power markets. In this paper, a new strategy for increasing the profits of wind resources is proposed. In the suggested strategy, a Generation Company (GenCo), who owns both wind and pumped-storage plants, self-schedules the integrated operation of them regarding the uncertainty of wind power generation. For presenting an integrated self-schedule and obtaining a real added value of the strategy, participation of the GenCo in energy and ancillary service markets is modeled. The self-scheduling strategy is based on stochastic programming techniques. Outputs of the problem include generation offers in day-ahead energy market and ancillary service markets, including spinning and regulation reserve markets. A Neural Network (NN) based technique is used for modeling the uncertainty of wind power production. The proposed strategy is tested on a real wind farm in mainland, Spain. Moreover, added value of the strategy is presented in different conditions of the market. [Copyright &y& Elsevier]

Abstract: Solar thermal electricity technologies are attractive alternatives to produce electricity by means of a renewable source. One of these technologies is parabolic trough collectors. In Spain, the sale of solar electricity to the national grid is primed. There are three main parameters that affect the behaviour of these plants: area of solar collector field, capacity of thermal storage tanks and power of the auxiliary system. In this paper, a simplified model of the plant is used to optimize the size of its components that produces the maximum yearly profit. The use of traditional methods of optimization is not possible and genetic algorithms have been used. An important feature of the model is that the minimum level of the electricity production of the block of power can be fixed. Once the optimization has been performed, the traditional parameters that characterize the dimension of the plant are analysed (the solar multiple and the capacity factor). For a gross power of 50 MW, the optimum collector area varies between 583,000 m2 and 749,860 m2 with a thermal storage between 6.55 h and 13.46 h respectively. The economic benefit is always higher than 19.30 M€ per year and the cost of the electricity produced is about 18.5 c€/kWh. [Copyright &y& Elsevier]

Abstract: While most of the studies that address competition between road and rail transport focus on national or international non-maritime shipments, there is practically no empirical evidence on the modal choice determinants of the inland leg of maritime shipments. This paper intends to fill that gap by estimating a modal choice model between road and rail transport on the inland leg of Spanish containerised maritime freight shipments, using a mixed logit model and stated preference techniques. The results obtained confirm the vital role that frequency plays in the relative competitiveness of rail transport and also provide subjective values of transport attributes that are deemed essential for an accurate cost-benefit analysis. [Copyright &y& Elsevier]

Abstract: The new EU challenge is to recover 70% by weight of C&D waste in 2020. Literature reveals that one major barrier is the lack of data. Therefore, this paper presents a model which allows technicians to estimate C&D waste during the design stage in order to promote prevention and recovery. The types and quantities of CW are estimated and managed according to EU guidelines, by building elements and specifically for each project. The model would allow detection of the source of the waste and to adopt other alternative procedures which delete hazardous waste and reduce CW. Likewise, it develops a systematic structure of the construction process, a waste classification system and some analytical expressions which are based on factors. These factors depend on technology and represent a standard on site. It would allow to develop a database of waste anywhere. A Spanish case study is covered. Factors were obtained by studying over 20 dwellings. The source and types of packaging waste, remains, soil and hazardous waste were estimated in detail and were compared with other studies. Results reveal that the model can be implemented in projects and the chances of reducing and recovery C&D waste could be increased, well above the EU challenge. [Copyright &y& Elsevier]

Abstract: Damage caused to objects of cultural heritage is one of the most serious detrimental effects of air pollutants. Within the 6th Framework Programme of the EU, the CULT-STRAT project is an inter-agency, multi-disciplinary project that has integrated research and monitoring information to provide answers to policy and management questions, which relate the effects of air pollutants on heritage and the management options available to mitigate them. The overall aim of the project has been to assess and predict the effects of different pollutants on materials and objects of cultural heritage in a multipollutant scenario and to identify indicators and thresholds levels of pollutants. These have been used for development of management strategies for sustainable maintenance and preventive conservation of European Cultural Heritage and air quality policy from continental to local scale. The present paper reports one of the studies carried out in the CULT-STRAT project at city level and focused on the town of Madrid (Spain). Different maps are shown for the present and possible future scenarios (2010 and 2020): inventory of stock of cultural heritage for each selected material, concentration of selected pollutants (SO2, NO2, O3 and PM10), corrosion (cast bronze) and recession (Portland limestone), exceedance of tolerable degradation thresholds for each material and corrosion-cultural heritage overlapped maps. [Copyright &y& Elsevier]

Abstract: Groundwater in Spain, as in other arid and semiarid countries worldwide, has been widely used in the expansion of irrigated agriculture. In the Spanish Mancha Occidental aquifer, the excessive, and sometimes illegal, water abstraction for irrigation has promoted outstanding socioeconomic development in the area, but it has also resulted in exploitation of the aquifer and degradation of valuable wetlands. Water policies implemented in the region have not yet managed to restore the aquifer and face strong social opposition. This paper uses a multi-scale modeling approach to explore the environmental and socio-economic impacts of alternative water conservation measures at the farm and basin levels. It also analyzes their comparative cost-effectiveness to help policy makers identify the least costly policy option for achieving the goal of the Mancha Occidental aquifer''s sustainability. To conduct this analysis, a Mathematical Programming Model has been developed to simulate: the closing-up and taxed-legalization of unlicensed wells, uniform volumetric and block-rate water prices, water quotas, and water markets. Aggregate results show that net social costs are not substantially different across policy option, so none of the considered policy options will be clearly more cost-effective than the others. However, there are significant differences between private and public costs (at the farm and sub-basin levels), which will be critical for determining the application in practice of these policies. Results show that controlling illegal water mining (through the legalization of unlicensed wells) is necessary, but is not sufficient to recover the aquifer. Rather, effective water management in this area will require the implementation of other water management policies as well. Among them, uniform volumetric and block-rate water pricing policies will entail the lowest net social cost, but will produce important income losses in the smallest and most water-intensive farms, which might put at risk the viability of these farms and the social acceptance of the policies. Further investigations on social costs, policy enforcement capacity and public participation in water management are highly recommended. [Copyright &y& Elsevier]

Abstract: This paper proposes a novel price forecasting method based on wavelet transform combined with ARIMA and GARCH models. By wavelet transform, the historical price series is decomposed and reconstructed into one approximation series and some detail series. Then each subseries can be separately predicted by a suitable time series model. The final forecast is obtained by composing the forecasted results of each subseries. This proposed method is examined on Spanish and PJM electricity markets and compared with some other forecasting methods. [ABSTRACT FROM AUTHOR]

Abstract: Over the last few years electronic commerce, e-commerce for short, has become one of the most accepted purchasing systems this having became the easiest way of accessing a large variety of goods. E-commerce provides: the possibility of comparing costs and bids without going to outlets and therefore, saving time and money; the availability of detailed characteristics of goods; the possibility of acquiring new goods available abroad. Moreover, the form of payments are getting progressively safer and more reliable on the Internet. In this paper we develop a mathematical model to study future short-term trends of e-commerce in Spain. To do this, we divide the total population into age groups and each age group into two subgroups: the first one consists of people adopting this technology and the second one who do not. Then, we consider a nonlinear diffusion model whose parameters are the innovation coefficients associated with each age group and related to advertising, and the imitation coefficients related to the influence of an adopting technology group on non-adopting group. These parameters are estimated by fitting the available real data from the Spanish Statistic Institute. Finally, an analysis of statistic sensitivity is included. [ABSTRACT FROM AUTHOR]

Abstract: Cocaine consumption is a social problem with acute consequences and its dependency can be regarded as a health concern of social transmission. This fact leads us to develop the idea that its transmission dynamics can be studied using epidemiological mathematical models. Under this point of view, in this paper we propose a network model to study the short-term evolution of the cocaine consumer subpopulations. The model parameters are obtained from data source and from an analogue continuous model. Sensitivity of the model parameters is studied. The parameters are associated with prevention and treatment policies and the sensitivity study gives us information about which parameters have more incidence on the future evolution of consumers. Results and discussion are also presented. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a mathematical model for alcohol consumption in Spanish population is proposed. Its parameters are estimated by fitting the model to real data from Spanish Ministry of Health. Predictions about the future behavior of the alcohol consumption in Spain are presented using this model. Results are applied to estimate the economic costs (sanitary and non-sanitary) assumed by Spanish society that are derived from this consumption. [ABSTRACT FROM AUTHOR]

Abstract: From February 2000 to December 2008 systematic measurements of CO2 ambient concentrations were taken using a MIR 9000 continuous infrared analyser in a rural area of the upper Spanish plateau. The wide database obtained has enabled us to quantify CO2 levels at the measuring site and describe daily and seasonal cycles as well as inter-annual variability. The daily cycle and seasonal variation were dominated by strong temperature inversions, TI, prevailing at the measuring site, up to 7.5°C per 100m, which largely contributed to trapping CO2 during night-time, particularly during the growing season. This paper presents the influence of TI on CO2 and describes the results using available TI values below 3°C as a filtering criterion addressed to minimise local disturbances. The filtered monthly means exhibited a seasonal variation characterised by a primary peak in May, a secondary weak peak in October and a minimum in July–August. Seasonal amplitude yielded 8.7ppm. Over the whole study period, the annual trend, estimated by means of a second order harmonic model applied to the monthly means (R 2 =95.6%), yielded a positive linear increase of 2.98 and a 0.64ppmyear−1 rise in the amplitude of the seasonal cycle. [Copyright &y& Elsevier]

Summary: Recharge is a key component of the hydrological balance in groundwater systems. Particularly in arid and semiarid settings recharge often takes place during isolated rainfall episodes. As a result pumping might cause groundwater levels to fall continuously for long periods of time, even if yearly abstractions remain below the average replenishment rate. Recharge is naturally difficult to quantify, as it depends on a complex variety of factors. Indirect techniques based on mathematical models have long since been advocated as valuable means to estimate recharge. This paper presents a methodology to estimate groundwater recharge in quick-response semiarid karst aquifers. Lumped and distributed models are used to evaluate the fraction of rainfall that ultimately results in aquifer recharge, as well as the correlation between the magnitude of rainfall events and infiltration rates. Modelling results are then compared with direct observations of the recharge processes and discussed to evaluate the implications of time scales. This study is demonstrated through a case-specific application to the Ventós aquifer, an intensively exploited carbonate system located in one of the driest areas of peninsular Spain. Overall, both approaches perform similarly, although the lumped model exhibits a better agreement with field records. Results reflect the nonlinear nature of the rainfall/recharge ratio. The fraction of rainfall that ultimately recharges the aquifer seems to increase exponentially with the magnitude of the event. [Copyright &y& Elsevier]

Abstract: This paper describes the characterization of ciders (both “natural” and sparkling cider) from the Principality of Asturias (northwest region of Spain) through the analysis of their protein content, based on their hydrophobic properties, and their foam characteristics. A reversed-phase high performance liquid chromatography (RP-HPLC) was applied to the protein analysis, and the foam parameters were measured with Bikerman’s method. Multivariate techniques allowed the authors to differentiate ciders on the basis of the press and foam taking technologies, and foam sensory quality. Feasible and robust models were constructed for classifying purposes. Higher than 95% correct classifications were obtained for differentiating ciders on the basis of the factors studied (cider making technology and foam sensory quality). The multivariate regression model computed allowed the authors to predict (correlation coefficients higher than 0.8) the foam parameters related to foam stability and bubble average lifetime in “natural” cider. [Copyright &y& Elsevier]

Abstract: This paper examines the link between nutrition label use and consumers’ healthier food choices. Label use is considered for the two main types of labels currently found on food products; nutrition facts panels and nutrition/health claims. This link is tested using a three-equation multivariate probit model. Data were obtained from an ad hoc survey conducted in two medium-sized Spanish cities. The results indicate that the use of nutrition information by consumers, whether this involves the fact panel or the claim labels, does influence consumer choice of healthier food products to the same extent, although different types of consumers use the various types of labels considered. [Copyright &y& Elsevier]

Abstract: The proximity of commercial harbours to residential areas and the growing environmental awareness of society have led most port authorities to include environmental management within their administration plan. Regarding water quality, it is necessary to have the capacity and tools to deal with contamination episodes that may damage marine ecosystems and human health, but also affect the normal functioning of harbours. This paper presents a description of the main pollutant sources in Tarragona Harbour (Spain), and a numerical analysis of several pollution episodes based on the Port Authority’s actual environmental concerns. The results show that pollution generated inside the harbour tends to remain confined within the port, whereas it is very likely that oil spills from a nearby monobuoy may affect the neighbouring beaches. The present combination of numerical models proves itself a useful tool to assess the environmental risk associated to harbour activities and potential pollution spills. [Copyright &y& Elsevier]

Abstract: Most of the marine pollution attributable to ship actions is associated with the illicit discharge of oily residues or ballast water, in what is commonly termed operational pollution. In the particular case of ballast water, careless disposal can lead to severe ecological damage, including the irreversible establishment of communities of invasive species. In its 2004 Convention on ballast water management, the International Maritime Organisation defined the measures to be followed to prevent these environmental issues, including the exchange with mid-oceanic water at a minimum distance from the shore. This paper uses two numerical models to analyse the effects of several factors on the dilution of a discharge from a ship moving in the Spanish Mediterranean waters, in order to determine under which conditions the environmental impact of the discharge will be minimum. The results highlight the dual role played by a freshwater plume, which may contribute either to decrease or to enhance the onshoreward transport of the discharged substance, and the relevance of the ship''s speed in determining the dilution rates. [Copyright &y& Elsevier]

: This paper empirically analyzes the indebtedness of the main companies in the Spanish hotel industry. In particular, it introduces a method to analyze the structures and dynamics of the largest companies in this sector. The method combines the Pearson correlation coefficient with the nearest neighbour single linkage clustering algorithm (Mantegna, R. N. (1999). Hierarchical structure in financial markets. The European Physical Journal B, 11, 193–197). The Pearson correlation coefficient determines a metric distance between two different multidimensional time series that is then used to construct a Minimal Spanning Tree. From this tree, an ultra metric distance that is used to derive the Hierarchical Tree can be computed. From the analysis of the time series data of companies included in the SABI, or the Iberian Balance Sheet Analysis System 2005, it is possible to derive a hierarchical organization of the Spanish hotel firms. In particular, different dynamic clusters of companies, which correspond to their common production and indebtedness strategies, can be detected. [Copyright &y& Elsevier]

Abstract: The present paper deals with the application of Tucker3 modelling to a sediment monitoring data set from the area of Mar Menor coastal lagoon (Spain). The aim of the study is to model and interpret the fractionation of heavy metals in the suspended particulate matter and sediment fractions resulting by sedimentation processes. Since the lagoon is seriously influenced by anthropogenic activities the modelling aims an assessment of the environmental hazard, too. After application of various scaling and centering procedures and estimation of the model dimensionality, an optimal (3, 3, 3) Tucker3 model was chosen for data interpretation. Using the model output (factor loadings connected to the four main core elements) it could be concluded that the heavy metal concentrations in the suspended particulate matter and sediment fractions increase in order Cu>Mn>Zn≈Pb>Cd and could be examined as estimation of basic levels for all heavy metals caused by different sedimentation processes. The second important core element summarizes the anthropogenic influence of the mining activity in the region. The third important core element shows the different mobility of the heavy metals. The fourth important core element should be related to the specific sediment formation at one of the sampling location. [Copyright &y& Elsevier]

Abstract: Trigeneration systems, also known as Combined Heat, Cooling and Power (CHCP) systems, are interesting alternatives to supply different energy services in urban districts and in large buildings, particularly in warm areas such as Mediterranean countries. These systems can provide substantial benefits from economic, energetic, and environmental viewpoints, since the cogenerated heat can be used for heating in winter as well as cooling in summer with an absorption refrigerator. This paper develops an optimization model using Mixed Integer Linear Programming (MILP) to determine the type, number and capacity of equipment in CHCP systems installed in the tertiary sector as well as to establish the optimal operation mode for the different plant components on an hour-by-hour basis throughout the year. The objective function to be minimized is the annual total cost. The optimization model considers the legal constraints imposed to feed the surplus autogenerated electricity into the grid at a regulated feed-in tariff. The optimization model is applied to design a system providing energy services for a hospital located in the city of Zaragoza (Spain). The effects of the financial market conditions and energy prices in the optimal structure of the system are analyzed. [Copyright &y& Elsevier]

The accuracy of environmental valuation studies relies, to a great extent, on the suitability of the proxy measures used to capture individuals' preferences. While important advances have been achieved in the last years concerning the characterization of the physical background in which recreational choices are made, Travel Cost Method applications have failed to consider the heterogeneity of landscape and the spatial configuration of land use. This paper presents an empirical application to forest recreation in Mallorca (Spain), implementing a random parameter logit model to evaluate in terms of goodness-of-fit, model predictions and welfare measurements the effects of environmental diversity on the recreational site-choice process. [Copyright &y& Elsevier]

Abstract: The need to obtain automatic filters to treat wind data is clear due to the huge amount of data available in any wind farm analysis. Automatic detection of performance deviations of wind turbines is required for maintenance purposes. In spite of some alarms being registered by the wind farm’s SCADA system, many times automatic use of real data use is not valid due to its low quality. In this paper, the problems to carry out the characterization of the turbines in a wind farm are stated and a new technique to filter the data is presented. The robust statistical technique of the Least Median of Squares (LMedS) combined with a random search is adapted to deal with this problem with promising results. A mathematical model representing the dependency of the wind turbine behaviour in function not only of the wind speed but also of other variables such as the direction of the wind is also proposed. The results achieved are tested with long term real data from wind farms in Spain. [Copyright &y& Elsevier]

Abstract: Most mathematical models of fish growth on commercial farms use the evolution of average weight during the growth period, without considering weight distribution. In this paper, quantile regression techniques were used to describe the evolution of weight distribution in 20 batches of gilthead sea bream (Sparus aurata) growing on a commercial fish farm in the Spanish Mediterranean. Different Thermal-unit Growth Coefficients (TGC) were obtained for several quantiles (5, 25, 50, 75 and 95%) in a group of heterogeneous batches, whereas a single TGC was observed in another group of homogeneous batches. Thus, the growth patterns observed were either homogeneous or heterogeneous. Discriminant analysis helped to identify variables that affected the classification of batches, namely, the coefficient of variation in initial weight and daily average temperature variation during the initial growth period. [Copyright &y& Elsevier]