7,781 research outputs found

    Towards Syntactic Iberian Polarity Classification

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    Lexicon-based methods using syntactic rules for polarity classification rely on parsers that are dependent on the language and on treebank guidelines. Thus, rules are also dependent and require adaptation, especially in multilingual scenarios. We tackle this challenge in the context of the Iberian Peninsula, releasing the first symbolic syntax-based Iberian system with rules shared across five official languages: Basque, Catalan, Galician, Portuguese and Spanish. The model is made available.Comment: 7 pages, 5 tables. Contribution to the 8th Workshop on Computational Approaches to Subjectivity, Sentiment and Social Media Analysis (WASSA-2017) at EMNLP 201

    Role of Mo in catalysts based on noble metals in hydrodeoxygenation reactions

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    The use of bio-energy as a renewable alternative to fossil fuels is nowadays attracting more and more attention. The bio-fuel from biomass seems to be a potential energy substitute for fossil fuels since it is a renewable resource that could contribute to sustainable development and global environmental preservation and it appears to have significant economic potential1. The problem is its high oxygen content, which gives undesirable properties for combustion. To remove oxygen, catalytic hydrodeoxygenation (HDO) reactions are carried out. Monometallic Mo/Si, Pt/Si as well as bimetallic PtMo/Si catalysts were prepared and evaluated in the hydrodeoxygenation (HDO)reaction of dibenzofurane (DBF) as a model molecule in biomass derived bio-oil.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    A Near-Infrared Template Derived from I Zw 1 for the FeII Emission in Active Galaxies

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    In AGN spectra, a series of FeII multiplets form a pseudo-continuum that extends from the ultraviolet to the near-infrared (NIR). This emission is believed to originate in the Broad Line Region (BLR), and it has been known for a long time that pure photoionization fails to reproduce it in the most extreme cases, as does the collisional-excitation alone. The most recent models by Sigut & Pradhan (2003) include details of the FeII ion microphysics and cover a wide range in ionization parameter log U_ion= (-3.0 -> -1.3) and density log n_H = (9.6 -> 12.6). With the aid of such models and a spectral synthesis approach, we study for the first time in detail the NIR emission of I Zw 1. The main goals are to confirm the role played by Ly\alpha-fluorescence mechanisms in the production of the FeII spectrum and to construct the first semi-empirical NIR FeII template that best represents this emission and can be used to subtract it in other sources. A good overall match between the observed FeII+MgII features with those predicted by the best fitted model is obtained, corroborating the Ly\alpha-fluorescence as a key process to understand the FeII spectrum. The best model is then adjusted by applying a deconvolution method on the observed FeII+MgII spectrum. The derived semi-empirical template is then fitted to the spectrum of Ark 564, suitably reproducing its observed FeII+MgII emission. Our approach extends the current set of available FeII templates into the NIR region.Comment: 47 pages, 5 tables, 12 figures. Accepted for publication in The Astrophysical Journa

    Numerical analysis of combustion noise in an atmospheric swirl-stabilized LDI burner through modal decomposition techniques

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    [EN] Combustion noise in gas turbine engines has recently become a relevant source of noise in the aircraft due to the appearance of new burner architectures that are intrinsically more unstable, and the optimization of other conventional noise sources in this mean of transport (e.g., jet, fan, airframe). In this work, a simulation setup for reactive conditions was prepared in the CONVERGE finite-volume package using the detailed chemistry SAGE solver to model the combustion of a benchmark case, which was solved using a LES approach with three different cell base sizes: 8,10,12 mm. A confined liquid-fueled swirl-stabilized burner located at the CORIA Laboratory, France, was used to validate the numerical results with the experimental measurements obtained at this facility. OH-PLIF measurements and PDA results for both phases were used to guarantee the accuracy of the numerical OH contours and the velocity profiles of both phases. These experimental measurements were collected at CORIA. After ensuring the stabilization of the numerical flame, the reactive simulations were extended with some adjustments in the time step to capture the acoustic motion. Several techniques like Fast Fourier Transform (FFT), Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD) were used to analyze these results and confirm the presence of a Precessing Vortex Core (PVC) and a Vortex Breakdown Bubble (VBB) during the coupling of pressure, axial velocity and fuel mass fraction in reactive conditions. Furthermore, the acoustic analysis performed with a Helmholtz solver proved that the second longitudinal mode of the chamber (329 Hz) was present in the pressure signal (300 Hz in the LES calculations) and resonated with the Vortex Breakdown Bubble (VBB). However, this dominant frequency did not appear in the frequency distribution of the OH mass fraction and no feedback interaction between the acoustic and the combustion happened. Thus, only combustion noise was obtained.This work was supported by the institutional program of the Korea Institute of Science and Technology (KIST, Project No. 2E32582).Broatch, A.; Carreres, M.; Garcia Tiscar, J.; Rodríguez-Pastor, M. (2023). Numerical analysis of combustion noise in an atmospheric swirl-stabilized LDI burner through modal decomposition techniques. Aerospace Science and Technology. 137:1-17. https://doi.org/10.1016/j.ast.2023.10828111713

    Inter-channel Granger Causality for Estimating EEG Phase Connectivity Patterns in Dyslexia

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    Methods like Electroencephalography (EEG) and magnetoencephalogram (MEG) record brain oscillations and provide an invaluable insight into healthy and pathological brain function. These signals are helpful to study and achieve an objective and early diagnosis of neural disorders as Developmental Dyslexia (DD). An atypical oscillatory sampling could cause the characteristic phonological difficulties of dyslexia at one or more temporal rates; in this sense, measuring the EEG signal can help to make an early diagnosis of DD. The LEEDUCA study conducted a series of EEG experiments on children listening to amplitude modulated (AM) noise with slow-rhythmic prosodic (0.5–1 Hz) to detect differences in perception of oscillatory ampling that could be associated with dyslexia. The evolution of each EEG channel has been studied in the frequency domain, obtaining the analytical phase using the Hilbert transform. Subsequently, the cause-effect relationships between channels in ach subject have been reflected thanks to Granger causality, obtaining matrices that reflect the interaction between the different parts of the brain. Hence, each subject was classified as belonging or not to the control group or the experimental group. For this purpose, two ensemble classification algorithms were compared, showing that both can reach acceptable classifying erformance in delta band with an accuracy up to 0.77, recall of 0.91 and AUC of 0.97 using Gradient Boosting classifier.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Modelling Hydrodynamic and Sedimentation Processes in Large Lowland Rivers: An Application to the Paraná River (Argentina)

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    In the last decade 1D, 2D and 3D numerical models have been extensively used to simulate river-floodplain hydraulics and sediment deposition processes in floodplains. Large river-floodplain ecosystems in lowland areas show characteristic reach lengths of the order of hundred of kilometers, floodplain widths of the order of tens of kilometers and river widths of the order of a few kilometers. The floodplain itself shows also a very complex geomorphology. Computationally intensive water flow and sediment transport models cannot take into account these peculiarities, and particularly the large time and space scales involved. On one hand, 1D models are not appropriated because the one-dimensional flow description is not representative of the complex flow pattern; on the other hand, higher dimensionality models, even if they can provide the necessary level of processes representation at small spatial scales, cannot be applied over large time and space scales due to the computational demands. An alternative to high resolution models is the implementation of quasi-2D models which can capture the fundamental characteristic of water flow and sediment dynamics in those situations. Thus, a compromise between computational costs and processes representation can be achieved. In this work a quasi-2D model, suitable for the time-dependent water and sediment transport processes simulation in large lowland river systems, including their floodplain, is presented. Water flow and sediment equations are represented by means of the interconnected irregular cells scheme. Different simplifications of 1D Saint Venant equations are used to represent the discharge laws between fluvial cells. Spatially-distributed transport and deposition of fine sediments throughout the river-floodplain system are simulated. The model is applied over a 208 km reach of the Paraná River between the cities of Diamante and Ramallo (Argentina) and involving a river-floodplain area of 8100 km². After calibration and validation, the model is applied to predict water and sediment dynamics during synthetically generated extraordinary floods of 100, 1000 and 10000 years return period. The potential impact of a 56 km long road embankment constructed across the entire floodplain was simulated. Results with and without the road embankment shows that upstream water levels, inundation extent, flow duration and sediment deposition increases in the presence of the embankment.National University of Rosario. Rosario, Argentina.University of Newcastle, Newcastle, Australia

    Profile and competences of Spanish industrial engineers in the European Higher Education Area (EHEA)

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    The aim of this document is to develop a clear definition of the role of the industrial engineer. This is important in the Spanish context, where the engineer curricula are evolved in a different way than in other countries, due to the role developed by the Professional Associations of Engineers and Technical Engineers. To this end we identify here the professional profiles to be expected of those graduating from such courses, the sectors where they are most likely to be recruited, and the context within which industrial engineers are employed. We deal with meanings and proposals for Industrial Engineers within a European context, drawing information from the academic debate which has been launched in a number of scientific publications. The text summarizes our personal reflections, which are integrated within a proposal for action intended as an additional contribution to the critical debate as to the situation, rather than a final responsePeer Reviewe

    Functional evaluation of coronary disease by CT angiography

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    Publisher Copyright: © 2015 American College of Cardiology Foundation.In recent years, several technical developments in the field of cardiac computed tomography (CT) have made possible the extraction of functional information from an anatomy-based examination. Several different lines have been explored and will be reviewed in the present paper, namely: 1) myocardial perfusion imaging; 2) transluminal attenuation gradients and corrected coronary opacification indexes; 3) fractional flow reserve computed from CT; and 4) extrapolation from atherosclerotic plaque characteristics. In view of these developments, cardiac CT has the potential to become in the near future a truly 2-in-1 noninvasive evaluation for coronary artery disease.publishersversionpublishe

    The 2-C-methylerythritol 4-phosphate pathway in melon is regulated by specialized isoforms for the first and last steps

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    The 2-C-methyl-d-erythritol-4-phosphate (MEP) pathway provides the precursors for the biosynthesis of plastidial isoprenoids, which include the carotenoid pigments of many fruits. We have analysed the genes encoding the seven enzymes of the MEP pathway in melon (Cucumis melo L.) and determined that the first one, 1-deoxyxylulose 5-phosphate synthase (DXS), and the last one, 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase (HDR), are represented in the genome as a small gene family and paralogous pair, respectively. In the case of DXS, three genes encode functional DXS activities which fall into previously established type I (CmDXS1) and II (CmDXS2a and CmDXS2b) categories, while a fourth DXS-like gene belonging to the type III group did not encode a protein with DXS activity. Their expression patterns and phylogenies suggest that CmDXS1 is functionally specialized for developmental and photosynthetic processes, while CmDXS2a and CmDXS2b are induced in flowers and ripening fruit of orange- (but not white-) fleshed varieties, coinciding with β-carotene accumulation. This is the first instance connecting type II DXS genes to specialized isoprenoid biosynthesis in the fruit of an agronomically important species. Two HDR paralogues were shown to encode functional enzymes, although only CmHDR1 was highly expressed in the tissues and developmental stages tested. Phylogenetic analysis showed that in cucurbits such as melon, these HDR paralogues probably arose through individual gene duplications in a common angiosperm ancestor, mimicking a prior division in gymnosperms, while other flowering plants, including apple, soy, canola, and poplar, acquired HDR duplicates recently as homoeologues through large-scale genome duplications. We report the influence of gene duplication history on the regulation of the MEP pathway in melon and the role of specialized MEP-pathway isoforms in providing precursors for β-carotene production in orange-fleshed melon varieties
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