Berrocoso J.D.,Complutense University of Madrid |
Mateos G.G.,University Polite Cnica Of Madrid |
Mateos G.G.,Complutense University of Madrid
Meat Science | Year: 2014
In total, 540 crossbred pigs with an initial body weight of 28.5. kg were used to investigate the effects of the net energy (NE) content (2.29, 2.33, 2.37, 2.41 and 2.45 Mcal/kg) of the diet on growth performance and carcass and meat quality traits of gilts, boars and immunocastrated males (IMC). An increase in dietary NE increased NE intake and decreased feed conversion ratio linearly. The IMC pigs showed greater feed intake and average daily gain than gilts and boars. Backfat depth increased and chilled and trimmed ham yield decreased, as the dietary NE increased. Backfat depth was greater for gilts and IMC than for boars. Also, gilts had greater carcass and loin yields than boars and IMC. Diets with the greater NE content were more appropriate for the production of heavy pigs. However, the economic interest of this practice needs further assessment. © 2014 Elsevier Ltd.
Garcia-Feced C.,University Polite Cnica Of Madrid |
Tempel D.J.,University of Minnesota |
Kelly M.,University of California at Berkeley
Journal of Forestry | Year: 2011
We show the use of an emerging technology, airborne light detection and ranging (LiDAR), to assess forest wildlife habitat by showing how it can improve the characterization of California spotted owl (Strix occidentalis occidentalis) nesting habitat. Large residual trees are important elements for many wildlife species and often, apparently, facilitate selection of habitat by spotted owls. However, we currently lack the ability to identify such trees over large spatial scales. We acquired multiple-return, high-resolution LiDAR data for a 107.1-km 2 area in the central Sierra Nevada, California. We surveyed for spotted owls within this area during 2007-2009 and located four nest trees. We then used the LiDAR data to measure the number, density, and pattern of residual trees (90-cm dbh) and to estimate canopy cover within 200 m of four nest trees. Nest trees were surrounded by large numbers of residual trees and high canopy cover. We believe that LiDAR would greatly benefit forest managers and scientists in the assessment of wildlife-habitat relationships and conservation of important wildlife species. © 2011 by the Society of American Foresters.
Mun&tild;oz-Anton J.,University Polite Cnica Of Madrid |
Biencinto M.,CIEMAT |
Applied Energy | Year: 2014
The efficiency of any thermal power plant is related to the maximum working temperature that some components can reach. Examples of material constraints are the first stage blades of a gas turbine or the receiver of a solar tower plant, but there are other temperature constraints, such as the ones related with the heat transfer fluid. Nowadays, this happens in the most common solar technology: parabolic trough collectors that use synthetic oil. This fluid must work below 400. °C. This limitation affects the power plant efficiency due to a poor Rankine cycle yield. To avoid this problem and go to higher temperatures, a gas can be used as heat transfer fluid, providing at the same time other significant advantages over synthetic oil: non-flammability and no environmental threats. The purpose of this paper is to justify the theoretical basis of the gas use in parabolic troughs and the problems related, and also to describe the test loop built at the PSA (Plataforma Solar de Almeri´a) in order to demonstrate the technical feasibility of this new technology, testing all components required to build a pre-commercial power plant. This paper describes the main features of this technology, the theoretical basis, the validation of the design tools and the results of the operation. Of them, the more important aspects are that high working pressure can reduce pumping power to adequate levels, that good controllability of the technology with hard solar transients can be achieved and that ball joints leaks problems detected appeared as the main inconvenience, but promising solution has been found. © 2014 Elsevier Ltd.
Illanes R.,University Polite Cnica Of Madrid |
De Francisco A.,University Polite Cnica Of Madrid |
De Blas M.,University of Navarra |
Torres J.L.,University of Navarra
Applied Energy | Year: 2014
It is known that simulation of PV systems permits to study their performance helping engineers to design them. This paper deals with the dynamic simulation and modelling of stand-alone PV systems by using state variables and numerical integration methods. Two PV systems have been modelled and simulated: a PV array directly connected to a resistive load and a PV array with batteries also connected to a resistive load. A double exponential model, together with the procedure 1 for temperature and irradiance corrections of the IEC 60891 standard, has been used to model the PV array and considering the general battery model of Coppety with some modifications, the system with batteries was simulated. The obtained results from the simulations and experimental tests have been analysed and have shown that this methodology is a good option to simulate these systems. © 2014 Elsevier Ltd.
Torres I.L.,University Polite Cnica Of Madrid |
Perez S.O.,Technical University of Madrid |
Robredo F.G.,Technical University of Madrid |
Belda C.F.,Comillas Pontifical University
Forest Science | Year: 2012
This study analyzes the stability of De Liocourt's distribution, investigating the influence of factors such as site index, recruitment, and basal area. It is proved that De Liocourt's distribution is not stable, and some simple models providing better fit to the stable diameter distribution of the stand than De Liocourt's are introduced. The stable diameter distributions obtained were characterized by a decrease in stem density in relation to the corresponding De Liocourt's distributions for low- and high-diameter classes and an increase for intermediate-diameter classes. Despite their instability, De Liocourt's distributions have shown a high degree of fit to the corresponding stable diameter distributions. The goodness of fit between both distributions was better for high recruitment, high site quality, and low basal area. © 2012 by the Society of American Foresters.
Iglesias-Pradas S.,University Polite Cnica Of Madrid |
Ruiz-de-Azcarate C.,University Polite Cnica Of Madrid |
Agudo-Peregrina A.F.,University Polite Cnica Of Madrid
Computers in Human Behavior | Year: 2014
In the past decades, online learning has transformed the educational landscape with the emergence of new ways to learn. This fact, together with recent changes in educational policy in Europe aiming to facilitate the incorporation of graduate students to the labor market, has provoked a shift on the delivery of instruction and on the role played by teachers and students, stressing the need for development of both basic and cross-curricular competencies. In parallel, the last years have witnessed the emergence of new educational disciplines that can take advantage of the information retrieved by technology-based online education in order to improve instruction, such as learning analytics.This study explores the applicability of learning analytics for prediction of development of two cross-curricular competencies - teamwork and commitment - based on the analysis of Moodle interaction data logs in a Master's Degree program at Universidad a Distancia de Madrid (UDIMA) where the students were education professionals. The results from the study question the suitability of a general interaction-based approach and show no relation between online activity indicators and teamwork and commitment acquisition. The discussion of results includes multiple recommendations for further research on this topic. © 2014 Elsevier Ltd.
Fernandez Serrano R.,CEDEX |
Fernandez Serrano R.,University Polite Cnica Of Madrid |
Fernandez Serrano R.,New York University |
Iskander M.,New York University |
Tabe K.,Sharda University
Geotechnique Letters | Year: 2011
A physical model based on transparent soil technology is presented as a novel laboratory tool for ground contamination research. The model aims to reproduce both unsaturated and saturated conditions within a Spanish soil formation known as Miga sand. A soil surrogate made of a waterabsorbing polymeric gel was employed. Multi-phase flow froma leaking underground storage tank was simulated in both saturated and unsaturated conditions in order to illustrate the usefulness of the technique in simulating a hypothetical spill of a light non-aqueous phase liquid under well-controlled test conditions. The plume observed was found to be spatially variable. The technique permits, for the first time, the simulation of specific grain size distributions in a transparent soil surrogate and visualization of plume development in three dimensions. Preliminary results indicate that the model is a potentially powerful tool for visualising pollutant transport in porous media. A brief description of the test setup, and a summary of the advantages, limitations, and prospective applications are presented.
Rodriguez Gonzalez A.B.,Rey Juan Carlos University |
Vinagre Diaz J.J.,Rey Juan Carlos University |
Vinagre Diaz J.J.,University Polite Cnica Of Madrid |
Wilby M.R.,Rey Juan Carlos University |
Wilby M.R.,University Polite Cnica Of Madrid
Energy Policy | Year: 2012
The European Union has unilaterally committed to a 20% reduction of the greenhouse gas emissions and another 20% increase in energy efficiency by 2020. This work presents Ecotax, an economic policy instrument that supports the simultaneous achievement of both objectives, in the building sector. The proposed instrument is a tax/subsidy scheme attached to the difference between the actual emissions and a specified target. It uses market pricing to value emissions trading price, and is directly integrated into the energy efficiency certification scheme. Thus, minimizing the administrative costs of its establishment. During the project phase, the tax/subsidy falls on the construction companies which facilitates the funding of innovation in technology. In the operation phase, it falls on proprietors or end-users, stimulating sustainable consuming habits. In both cases, the administration acts as an intermediary, channeling funds from low to high energy efficiency agents, inside and outside the sector itself. Although the instrument is specifically proposed for the building sector, it is easily translatable to other sectors that are not necessarily included in the emission allowance trading scheme of the European Union. © 2012 Elsevier Ltd.
Alvarado A.,University of Costa Rica |
Forsythe W.,University of Costa Rica |
Algeet-Abarquero N.,University of Costa Rica |
Algeet-Abarquero N.,University Polite Cnica Of Madrid
Catena | Year: 2014
High rates of soil loss are usually assumed under teak (Tectona grandis L.f.) plantations and some debate has been created about this during recent years. We analyzed the processes of soil loss and accumulation in a case study and performed a critical review of literature from other studies, due to the shortage of field experimental data from around the world to sustain this theory. The case study was established in Alfisols and slopes ranging from 30 to 60% in Guanacaste, Costa Rica, and compares secondary forests with mature teak plantations and young teak plantations under different management regimes. Over a period of 14. months with higher rainfall than the regional average, very little soil loss was registered in the teak plantations of Guanacaste, although there were slight differences between treatments (1-4. mm), while soil accumulation was measured in secondary forests (4. mm). A number of other authors also report low levels of soil loss in teak plantations and those studies in which high erosion rates have been identified tend to be associated with teak plantations where fires are a common phenomenon. Hence, we conclude that poor forest management (prescribed fires, machinery, extremely steep slopes, previous land use, etc.) rather than the nature of the teak itself causes the high rates of erosion. © 2014 Elsevier B.V.
Pineda-Pardo J.A.,University Polite Cnica Of Madrid |
Brun&tild;a R.,University Polite Cnica Of Madrid |
Woolrich M.,University of Oxford |
Marcos A.,University of Oxford |
And 4 more authors.
NeuroImage | Year: 2014
Whole brain resting state connectivity is a promising biomarker that might help to obtain an early diagnosis in many neurological diseases, such as dementia. Inferring resting-state connectivity is often based on correlations, which are sensitive to indirect connections, leading to an inaccurate representation of the real backbone of the network. The precision matrix is a better representation for whole brain connectivity, as it considers only direct connections. The network structure can be estimated using the graphical lasso (GL), which achieves sparsity through l1-regularization on the precision matrix. In this paper, we propose a structural connectivity adaptive version of the GL, where weaker anatomical connections are represented as stronger penalties on the corresponding functional connections. We applied beamformer source reconstruction to the resting state MEG recordings of 81 subjects, where 29 were healthy controls, 22 were single-domain amnestic Mild Cognitive Impaired (MCI), and 30 were multiple-domain amnestic MCI. An atlas-based anatomical parcellation of 66 regions was obtained for each subject, and time series were assigned to each of the regions. The fiber densities between the regions, obtained with deterministic tractography from diffusion-weighted MRI, were used to define the anatomical connectivity. Precision matrices were obtained with the region specific time series in five different frequency bands. We compared our method with the traditional GL and a functional adaptive version of the GL, in terms of log-likelihood and classification accuracies between the three groups. We conclude that introducing an anatomical prior improves the expressivity of the model and, in most cases, leads to a better classification between groups. © 2014 Elsevier Inc.