Time filter

Source Type

Santiago de Compostela, Spain

The University of Santiago de Compostela - USC is a public university located in the city of Santiago de Compostela, Galicia, Spain. A second campus is located in Lugo, Galicia. It is one of the world's oldest universities in continuous operation.The university traces its roots back to 1495, when a school was opened in Santiago. In 1504, Pope Julius II approved the foundation of a university in Santiago but "the bull for its creation was not granted by Clement VII until 1526". In 1555 the institute began to separate itself from strictly religious instruction with the help of Cardinal Juan Álvarez de Toledo and started to work towards developing other academic fields, including the emerging science fields.Today the university's facilities cover more than 1,300,000 square meters . In terms of human resources, the university has more than 2,000 teachers involved in study and research, over 42,000 students, and more than 1,000 people working in administration and services. Moreover, in 2009, the University received the accreditation of Campus of International Excellence by the Ministry of Education , recognising USC as one of the most prestigious universities in Spain.The university ranks 5th in Spain's best universities ranking by Complutense University of Madrid and IAIF and 4th amongst public universities. Wikipedia.

Martinez-Nunez E.,University of Santiago de Compostela
Physical Chemistry Chemical Physics | Year: 2015

Very recently, we proposed an automated method for finding transition states of chemical reactions using dynamics simulations; the method has been termed Transition State Search using Chemical Dynamics Simulations (TSSCDS) (E. Martínez-Núñez, J. Comput. Chem., 2015, 36, 222-234). In the present work, an improved automated search procedure is developed, which consists of iteratively running different ensembles of trajectories initialized at different minima. The iterative TSSCDS method is applied to the complex C3H4O system, obtaining a total of 66 different minima and 276 transition states. With the obtained transition states and paths, statistical RRKM calculations and Kinetic Monte Carlo simulations are carried out to study the fragmentation dynamics of propenal, which is the global minimum of the system. The kinetic simulations provide a (three-body dissociation)/(CO elimination) ratio of 1.49 for an excitation energy of 148 kcal mol-1, which agrees well with the corresponding value obtained in the photolysis of propenal at 193 nm (1.1), suggesting that at least these two channels: three-body dissociation (to give H2 + CO + C2H2) and CO elimination occur on the ground electronic state. This journal is © the Owner Societies.

Wang X.-N.,Central China Normal University | Wang X.-N.,Lawrence Berkeley National Laboratory | Zhu Y.,University of Santiago de Compostela
Nuclear Physics A | Year: 2014

Medium modification of γ-tagged jets in high-energy heavy-ion collisions is investigated within a linearized Boltzmann transport model which includes both elastic parton scattering and induced gluon emission. In Pb + Pb collisions at s=2.76TeV, a γ-tagged jet is seen to lose 15% of its energy at 0-10% central collisions. Simulations also point to a sizable azimuthal angle broadening of γ-tagged jets at the tail of a distribution which should be measurable when experimental errors are significantly reduced. An enhancement at large zjet=pL/Ejet in jet fragmentation function at the Large Hadron Collider (LHC) can be attributed to the dominance of leading particles in the reconstructed jet. A γ-tagged jet fragmentation function is shown to be more sensitive to jet quenching, therefore a better probe of the jet transport parameter. © 2014 Elsevier B.V.

Astariz S.,University of Santiago de Compostela | Iglesias G.,University of Plymouth
Energy | Year: 2016

Wind speed fluctuates widely, and with wind power depending on the wind speed cubed, the variability in the power output of offshore wind farms is by no means negligible. This variability can hinder the penetration of offshore wind energy into the electricity market due to the resulting instability in the power system and the associated balancing costs. Diversified renewable systems have been proposed as a solution to achieve a smoother power output. On this basis, this study focuses on the benefits in terms of power smoothing and reduced downtime of combined offshore wind and wave farms relative to the standalone alternatives. This analysis is carried out through two case studies, corresponding to wind farms currently in operation, and based on extensive wave and wind data. It is found that: (i) reductions of up to 87% and 6% in downtime and power variability, respectively, can be achieved through co-located wind-wave farms; (ii) the combination of wave and offshore wind is more effective in reducing downtime and variability at sites where both resources are only weakly correlated; and (iii) co-located farms are a opportunity to increase the power production from renewables in a cost-competitive way. © 2016 Elsevier Ltd.

Bueno-Crespo A.,San Antonio de Murcia Catholic University | Garcia-Laencina P.J.,University of Santiago de Compostela | Sancho-Gomez J.-L.,Technical University of Cartagena
Neural Networks | Year: 2013

Selection of the optimal neural architecture to solve a pattern classification problem entails to choose the relevant input units, the number of hidden neurons and its corresponding interconnection weights. This problem has been widely studied in many research works but their solutions usually involve excessive computational cost in most of the problems and they do not provide a unique solution. This paper proposes a new technique to efficiently design the MultiLayer Perceptron (MLP) architecture for classification using the Extreme Learning Machine (ELM) algorithm. The proposed method provides a high generalization capability and a unique solution for the architecture design. Moreover, the selected final network only retains those input connections that are relevant for the classification task. Experimental results show these advantages. © 2013 Elsevier Ltd.

Pettazzi A.,University of Santiago de Compostela
Photodermatology Photoimmunology and Photomedicine | Year: 2010

Commercial devices measuring UV radiation are available on the market at affordable prices. This work presents the response of six commercial devices in comparison to UV index measurements and in relation to the guidelines provided by the INTERSUN programme. Taking everything into account, overestimated or non-standard data, and ambiguous or incomplete information was found. Instead of using these gadgets, people should refer to official information and advice provided by health and weather services. © 2010 John Wiley & Sons A/S.

Sasian J.,University of Arizona | Acosta E.,University of Santiago de Compostela
Optics Express | Year: 2014

We show that spherical aberration of all orders can be generated as an extrinsic aberration in a system of axially translating plates. Some practical examples are provided. In particular for two phase plates that are 10 mm in diameter it is possible to generate from -10 to 10 waves of fourthorder spherical aberration with an axial displacement of +/- 0.65 mm. We also apply the phenomenon of extrinsic aberration for the generation of a conical wavefront and other non-axially symmetric wavefronts, in other words we propose what can be called a generalized zoom plate. © 2014 Optical Society of America.

Bigazzi F.,University of Florence | Cotrone A.L.,University of Turin | Mas J.,University of Santiago de Compostela | Mayerson D.,Catholic University of Leuven | Tarrio J.,University Utrecht
Journal of High Energy Physics | Year: 2011

We present the string dual to SU(Nc) N = 4 SYM, coupled to Nf massless fundamental flavors, at finite temperature and baryon density. The solution is determined by two dimensionless parameters, both depending on the 't Hooft coupling ?h at the scale set by the temperature T: ?h ? ?hNf /Nc, weighting the backreaction of the flavor fields and δ̃ ∼ λ1/2 h nb/(NfT3), where nb is the baryon density. For small values of these two parameters the solution is given analytically up to second order. We study the thermodynamics of the system in the canonical and grand-canonical ensembles. We then analyze the energy loss of partons moving through the plasma, computing the jet quenching parameter and studying its dependence on the baryon density. Finally, we analyze certain "optical" properties of the plasma. The whole setup is generalized to non abelian strongly coupled plasmas engineered on D3-D7 systems with D3-branes placed at the tip of a generic singular Calabi-Yau cone. In all the cases, fundamental matter fields are introduced by means of homogeneously smeared D7-branes and the flavor symmetry group is thus a product of abelian factors.

Perez-Sayans M.,University of Santiago de Compostela
Applied Immunohistochemistry and Molecular Morphology | Year: 2015

Oral squamous cell carcinoma is the most common neoplasia of the mouth. Downregulation of p16 (a cyclin-dependent kinase inhibitor) has been reported for mouth cancer and it is believed that its inactivation is an early event in oral carcinogenesis. The goal of this article is to quantitatively report expression of p16 and the state of methylation in oral squamous cell carcinoma, and evaluate its relationship with the clinical and prognostic factors, in addition to setting out a multivariate model that predicts survival. The mean expression of p16 was 7.70 (SD=14.07) (F=0.894; P=0.449). According to the semiquantitative analysis, there were statistically significant differences, where 19 cases were negative (<2 %), 11 at initial stages, and 8 at advanced stages (χ=6.016; P<0.05). The methylation of p16 was not associated with any of the clinical or pathologic variables. Kaplan-Meier curve showed a better survival for patients in initial stages (40.72 mo) compared to those in advanced stages (28.6 mo) (P<0.01). Survival was also reduced in a statistically significant manner in patients with any degree of dysplasia in the adjacent margin (P<0.05). During univariate Cox regression analysis, it was observed that individuals with relapse had a higher risk (almost 9 times higher) [P<0.001; hazard ratio=8.91; 95% confidence interval (CI), 4.18-19.02]. During the Cox multivariate analysis for each unit of decrease in p16, the risk increased by 1.06) (P<0.05; hazard ratio=0.94; 95% CI, 0.89-1.00). p16 expression is reduced with advancing tumor stage and its gene silencing is associated with an increased risk of death. © 2015 Lippincott Williams & Wilkins, Inc.

Garcia C.,University of Santiago de Compostela | Avila V.,University of Vigo | Quesada H.,University of Vigo | Caballero A.,University of Vigo
Genetics | Year: 2012

We present a transcriptomic analysis aimed at investigating whether the changes in gene expression that occur under inbreeding generally reduce or enhance inbreeding depression. Discerning between these two alternatives can be addressed only when both changes in expression due to inbreeding and to inbreeding depression are estimated simultaneously. We used Affymetrix 2.0 arrays to study the changes in gene expression associated with both inbreeding and inbreeding depression for fitness in four sets of inbred sublines of Drosophila melanogaster. We found that for most genes showing changes in expression associated with inbreeding, the least depressed sublines were those showing the largest departures in expression from that of the outbred control. This suggests a pattern consistent with a protective role of expression changes against inbreeding effects, and would reveal a new dimension of the transcriptomics of inbreeding. The variation in depression observed could then be due not only to the genetic damages primarily originating that depression, but also possibly to differences in the ability to carry out the appropriate adjustments in gene expression to cope with the inbreeding. We also found that these expression changes with a putative protective role against inbreeding effects show a clear specificity on RNA synthesis and splicing and energy derivation functions. © 2012 by the Genetics Society of America.

Fattorini S.,University of Milan Bicocca | Fattorini S.,University of The Azores | Baselga A.,University of Santiago de Compostela
Insect Conservation and Diversity | Year: 2012

1.We used a hyperdiverse invertebrate group, tenebrionid beetles, to test competing hypotheses about the factors correlated with the spatial variation in species richness and composition across Europe. 2.We considered the following hypotheses for explaining variation in species richness, (i) spatial heterogeneity, (ii) environmental energy, and (iii) dispersal limitation and post-glacial recolonisation, and the following hypotheses for variation in species composition, (i) current climate, (ii) Pleistocene glaciations, and (iii) neutral dynamics. 3.We used inventories of 36 European territories, built from a database containing the distributions of 1010 species or subspecies. Area, spatial position, and topographical and climatic variables were used as predictors in regression (richness) and constrained analysis of principal coordinates (composition) analyses. 4.The latitudinal richness gradient found in European tenebrionids was mostly explained by the joint effect of environmental and spatial variables, supporting the climate and incomplete recolonisation hypotheses. 5.A parabolic relationship of endemism with longitude points to the presence of centres of endemism in the Iberian Peninsula and the Balkans. Current climatic conditions alone were not sufficient to explain spatial turnover patterns of European tenebrionids, which are largely influenced by spatial factors. 6.Both the Pleistocene glaciations and neutral hypotheses were supported, but the fact that turnover is not uniform across Europe suggests that the historical effects of Pleistocene glaciations had a deeper impact on tenebrionid assemblages than neutral dynamics. Thus, variation in species richness seems more directly controlled by climatic factors, whereas geographical constraints related to dispersal limitation or stochastic colonisation events influenced species composition. © 2011 The Royal Entomological Society.

Toro E.F.,University of Trento | Vazquez-Cendon M.E.,University of Santiago de Compostela
Computers and Fluids | Year: 2012

In this paper we consider two aspects of flux splitting, one at the level of the differential equations and another concerned with numerical methods to discretize the resulting problems. In this framework there are various choices for the splitting at the level of the PDEs and many choices for their numerical discretization. Some of the existing flux splitting schemes fall within this framework. For the Euler equations we propose a new flux splitting and study the associated two systems of differential equations, called the advection system and the pressure system. For each of the splittings studied we analyse the resulting two systems of differential equations and propose discretization schemes of the Godunov type. These schemes are simple, robust and accurate when compared with existing methods. Moreover, they enjoy a most desirable property: recognition of contact discontinuities and shear waves. © 2012 Elsevier Ltd.

Lafarge T.,U.S. National Institute of Standards and Technology | Possolo A.,U.S. National Institute of Standards and Technology | Pateiro-Lopez B.,University of Santiago de Compostela | Dunkers J.P.,U.S. National Institute of Standards and Technology
Journal of Statistical Software | Year: 2014

This work presents the implementation in R of the -shape of a finite set of points in the three-dimensional space ℝ3. This geometric structure generalizes the convex hull and allows to recover the shape of non-convex and even non-connected sets in 3D, given a random sample of points taken into it. Besides the computation of the α-shape, the R package alphashape3d provides users with tools to facilitate the three-dimensional graphical visualization of the estimated set as well as the computation of important characteristics such as the connected components or the volume, among others.

Pardo V.,University of California at Davis | Pardo V.,University of Santiago de Compostela | Pickett W.E.,University of California at Davis
Physical Review Letters | Year: 2010

The recently synthesized layered nickelate La4Ni 3O8, with its cupratelike NiO2 layers, seemingly requires a Ni1 (d8)+2Ni2(d9) charge order, together with strong correlation effects, to account for its insulating behavior. Using density functional methods including strong intra-atomic repulsion (Hubbard U), we obtain an insulating state via a new mechanism: without charge order, correlated (Mott) insulating behavior arises based on quantum-coupled, spin-aligned molecular Ni2-Ni1-Ni2 dz2 trimer states across the trilayer (molecular rather than atomic states), with antiferromagnetic ordering within layers. The weak and frustrated magnetic coupling between cells may account for the small spin entropy that is removed at the Néel transition at 105 K and the lack of any diffraction peak at the Néel point. © 2010 The American Physical Society.

Alonso-Meijide J.M.,University of Santiago de Compostela | Carreras F.,Polytechnic University of Catalonia
Expert Systems with Applications | Year: 2011

We propose a modification of the Shapley value for monotonic games with a coalition structure. The resulting coalitional value is a twofold extension of the Shapley value in the following sense: (1) the amount obtained by any union coincides with the Shapley value of the union in the quotient game; and (2) the players of the union share this amount proportionally to their Shapley value in the original game (i.e.; without unions). We provide axiomatic characterizations of this value close to those existing in the literature for the Owen value and include applications to coalition formation in bankruptcy and voting problems. © 2010 Elsevier Ltd. All rights reserved.

Morais M.,Polytechnic Institute of Braganca | Moreira L.,Polytechnic Institute of Braganca | Feas X.,University of Santiago de Compostela | Estevinho L.M.,Polytechnic Institute of Braganca
Food and Chemical Toxicology | Year: 2011

The aim of this study was to determine the palynological origin, phenolic content, antioxidant and antimicrobial properties of pollen from five Portuguese Natural-Parks [Parque Nacional Peneda Gerês (PNPG); Parque Natural do Montesinho (PNM); Parque Natural do Alvão (PNA); Parque Natural da Serra da Estrela (PNSE) and Parque Natural do Douro Internacional (PNDI)]. Eight families were found in the mixture of bee pollen: Rosaceae, Cistaceae, Boraginaceae, Asteraceae, Fagaceae, Ericaeae, Myrtaceae and Fabaceae. The phenolic compounds content, determined by the Folin-Ciocalteu method, varied between 10.5 and 16.8mg of gallic acid equivalents/g of extract (mg GAE/g) found in bee pollen from PNM and PNDI, respectively. The free radical scavenging measured showed the highest effective extract - PNM with EC50 2.16, followed by PND with 2.24mg/mL. In the β-carotene bleaching assay the same behaviour as in the DPPH method was verified. We also verified that the presence of pollen differentially affected the growth of bacteria Gram-positive, Gram-negative and yeasts under study, depending this on the microorganism and the pollen used. This is an important study since, as far we know, it is the first time that Portuguese bee pollen from Natural Parks was studied, and their characterization can increase their economic value. © 2011.

Reboredo J.C.,University of Santiago de Compostela
Renewable and Sustainable Energy Reviews | Year: 2015

Renewable energy deployment is arguably the best way to address the challenges of climate change. This paper investigates convergence in the contribution of renewable energies to the energy supply for a broad set of countries for the period 1990 to 2010. Using a nonlinear time-varying coefficients factor model and a pooled mean group estimator for dynamic heterogeneous panels, our empirical results mainly suggest divergence and dissimilar temporal patterns in the contribution of renewable energies to the energy supply. Only a small number of countries with significant and growing renewable energy sectors display convergence. Our results point to uneven efforts to develop sustainable energies across countries, indicating that greater international cooperation is required in order to push more sustainable development. © 2015 Elsevier Ltd. All rights reserved.

Baselga A.,University of Santiago de Compostela | Leprieur F.,Montpellier University
Methods in Ecology and Evolution | Year: 2015

Two alternative frameworks have been proposed to partition compositional dissimilarity into replacement and nestedness-resultant component or into replacement and richness-difference components. These are, respectively, the BAS (Baselga 2010, Global Ecology and Biogeography, 19, 134-143) and POD (Podani & Schmera . Oikos, 120, 1625-1638) frameworks. We conduct a systematic comparison of parallel components in alternative approaches. We test whether the replacement components derived from the BAS and POD frameworks are independent of richness difference. We also evaluate whether previously reported tests of monotonicity between indices and ecological processes are informative to assess the performance of indices. Finally, we illustrate the consequences of differences between the BAS and POD frameworks using the North American freshwater fish fauna as an empirical example. In the BAS framework, the nestedness-resultant component (βjne or βsne) accounts only for richness differences derived from nested patterns while, in the POD framework, richness-difference dissimilarity (βrich or βrich.s) accounts for all kind of richness differences. Likewise, the replacement components of both alternative methods account for different concepts. Only the replacement component of the BAS framework (βjtu or βsim) is independent of richness difference, while the parallel component in the POD framework (β-3 or β-3.s) is not (i.e. it is mathematically constrained by richness difference). Therefore, only the BAS framework allows separating (i) the variation in species composition derived from species replacement which is independent of richness difference (i.e. not mathematically constrained by it) and (ii) the variation in species composition derived from nested patterns. © 2015 British Ecological Society.

Armesto N.,University of Santiago de Compostela | Gulhan D.C.,Massachusetts Institute of Technology | Milhano J.G.,University of Lisbon | Milhano J.G.,CERN
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2015

Centrality selection has been observed to have a large effect on jet observables in pPb collisions at the Large Hadron Collider, stronger than that predicted by the nuclear modification of parton densities. We study to which extent simple considerations of energy-momentum conservation which link the hard process with the underlying event that provides the centrality estimator, affect jets observables in such collisions. We develop a simplistic approach that considers first the production of jets in a pp collision as described by PYTHIA. From each pp collision, the value of the energy of the parton from the proton participating in the hard scattering is extracted. Then, the underlying event is generated simulating a pPb collision through HIJING, but with the energy of the proton decreased according to the value extracted in the previous step, and both collisions are added. This model is able to capture the bulk of the centrality effect for central to semicentral collisions, for the two available sets of data: dijets from the CMS Collaboration and single jets from the ATLAS Collaboration. As expected, the model fails for peripheral collisions where very few nucleons from Pb participate. © 2015.

Maneiro J.R.,Complejo Hospitalario Universitario Of Santiago Of Compostela | Salgado E.,Complejo Hospitalario Universitario Of Santiago Of Compostela | Gomez-Reino J.J.,Complejo Hospitalario Universitario Of Santiago Of Compostela | Gomez-Reino J.J.,University of Santiago de Compostela
JAMA Internal Medicine | Year: 2013

IMPORTANCE Knowledge of the immunogenicity of biologic agents may be helpful for the development of strategies for treatment of chronic immune-mediated inflammatory diseases. OBJECTIVE To summarize the influence of antibodies against biologic agents (AABs [seropositivity]) on efficacy and safety in immune-mediated inflammatory diseases. DATA SOURCES MEDLINE, EMBASE, Cochrane Library, and theWeb of Knowledge were searched for articles published in English, Spanish, French, Italian, or Portuguese between 2000 and March 2012. The search strategy focused on synonyms of diseases, immunogenicity, and biologic agents. Abstracts from 2001 to 2011 of the European League Against Rheumatism and American College of Rheumatology congresses were also included. STUDY SELECTION The selection criteria were (1) observational or interventional studies in rheumatoid arthritis, juvenile idiopathic arthritis, inflammatory bowel disease, spondyloarthritis, and psoriasis; (2) studies including patients who received biologic agents; and (3) studies collecting data on AABs. DATA EXTRACTIONANDSYNTHESIS Data collected included publication details, study design, characteristics of patients and treatments, presence of antibodies, and definition of response. MAIN OUTCOMES AND MEASURES The primary end pointwas the association of AABs with response to treatment. Secondary end points were the association of AABs with safety, the association of AABs with concentration of the drug, and the influence of use of concomitant immunosuppressive therapy in the formation of AABs. RESULTS The search captured 10 728 articles and abstracts. By hand and reverse search, 31 articleswere additionally included. After evaluation of the full reports, 60 referenceswere selected. They included 59 studies of anti-tumor necrosis factor monoclonal antibodies: 1 with etanercept, 2 with rituximab, and 2 with abatacept. In rheumatoid arthritis but not in inflammatory bowel disease or spondyloarthritis, seropositive patients presented worse clinical response at 6 months or less (odds ratio [OR],0.03; 95%CI,0.01-0.21), and at 6 months or more (0.03; 0.00-0.30) by meta-analysis. In rheumatoid arthritis, discontinuation of the biologic agent for all reasonswas more common in seropositive patients (OR, 3.53; 95%CI, 1.60-7.82). In all conditions, seropositive patients had a higher risk of hypersensitivity reactions (OR, 3.97; 95%CI, 2.36-6.67).Overall, concomitant treatment with disease-modifying antirheumatic drugs, including azathioprine, decreased the risk of seropositivity (OR,0.32; 95%CI,0.25-0.42). CONCLUSIONS AND RELEVANCE Presence of antibodies against anti-tumor necrosis factor monoclonal antibodies confers a risk of discontinuation of treatment in rheumatoid arthritis and a risk of development of hypersensitivity reactions in all immune-mediated inflammatory diseases. The combined use of anti-tumor necrosis factor monoclonal antibodies and disease-modifying antirheumatic drugs reduces the development of antibodies and subsequent risks. Information on other biologic agents is fragmentary.

Calo-Fernandez B.,University of Santiago de Compostela | Martinez-Hurtado J.L.,University of Cambridge
Pharmaceuticals | Year: 2012

Patents for several biologic blockbusters will expire in the next few years. The arrival of biosimilars, the biologic equivalent of chemical generics, will have an impact on the current biopharmaceuticals market. Five core capabilities have been identified as paramount for those companies aiming to enter the biosimilars market: research and development, manufacturing, supporting activities, marketing, and lobbying. Understanding the importance of each of these capabilities will be key to maximising the value generated from the biologics patent cliff.

The reductive activation of mitomycin C in aqueous bicarbonate buffer resulted in the formation of a previously unknown compound, characterized as an oxazolidinone derivative of cis-1-hydroxy-2,7-diaminomitosene. This compound is the result of a cyclization reaction of bicarbonate with the aziridine ring of aziridinomitosene, and was observed at bicarbonate concentrations close to those present in physiological plasma. © 2009 Elsevier Ltd. All rights reserved.

Quan Y.,University of California at Davis | Pardo V.,University of California at Davis | Pardo V.,University of Santiago de Compostela | Pickett W.E.,University of California at Davis
Physical Review Letters | Year: 2012

While the formal valence and charge state concepts have been tremendously important in materials physics and chemistry, their very loose connection to actual charge leads to uncertainties in modeling behavior and interpreting data. We point out, taking several transition metal oxides (La2VCuO 6, YNiO3, CaFeO3, AgNiO2, V 4O7) as examples, that while dividing the crystal charge into atomic contributions is an ill-posed activity, the 3d occupation of a cation (and more particularly, differences) is readily available in first principles calculations. We discuss these examples, which include distinct charge states and charge-order (or disproportionation) systems, where different "charge states" of cations have identical 3d orbital occupation. Implications for theoretical modeling of such charge states and charge-ordering mechanisms are discussed. © 2012 American Physical Society.

Hollowood T.J.,University of Swansea | Miramontes J.L.,University of Santiago de Compostela
Journal of High Energy Physics | Year: 2011

In this note, we summarize recent progress in constructing and then semiclassically quantizing solitons, or non-abelian Q-balls, in the symmetric space sine-Gordon theories. We then consider the images of these solitons in the related constrained sigma model, which are the dyonic giant magnons on the string theory world-sheet. Focussing on the case of the symmetric space S5, we perform a semi-classical quantization of the solitons and magnons and show that both lead to Chern-Simons quantum mechanics on the internal moduli space which is a real Grassmannian SO(4)/SO(2) × SO(2) but - importantly - with a different coupling constant. Quantizing this system shows that both the Q-balls and magnons come in a tower of states transforming in symmetric representations of the SO(4) symmetry group; however, the former come in a finite tower whereas the latter come in the well-known infinite tower of dyonic giant magnons. © SISSA 2011.

Hollowood T.J.,University of Swansea | Miramontes J.L.,University of Santiago de Compostela
Journal of High Energy Physics | Year: 2011

The generalized symmetric space sine-Gordon theories are a series of 1 + 1- integrable field theories that are classically equivalent to superstrings on symmetric space spacetimes F/G. They are formulated in terms of a semi-symmetric space as a gauged WZW model with fermions and a potential term to deform it away from the conformal fixed point. We consider in particular the case of PSU(2, 2|4)/Sp(2, 2) × Sp(4) which corresponds to AdS5× S5. We argue that the infinite tower of conserved charges of these theories includes an exotic N = (8, 8) supersymmetry that is realized in a mildy nonlocal way at the Lagrangian level. The supersymmetry is associated to a double central extension of the superalgebra psu(2|2) ⊕ psu(2|2) and includes a non-trivial R symmetry algebra corresponding to global gauge transformations, as well as 2-dimensional spacetime translations. We then explicitly construct soliton solutions and show that they carry an internal moduli superspace ℂℙ2|1 × ℂℙ2|1 with both bosonic and Grassmann collective coordinates. We show how to semi-classical quantize the solitons by writing an effective quantum mechanical system on the moduli space which takes the form of a co-adjoint orbit of SU(2|2)×2. The spectrum consists of a tower of massive states in the short, or atypical, symmetric representations, just as the giant magnon states of the string world sheet theory, although here the tower is truncated. © SISSA 2011.

Basiilio N.,Singular | Garcia-Rio L.,Singular | Martiin-Pastor M.,University of Santiago de Compostela
Langmuir | Year: 2012

The self-aggregation of five amphiphilic p-sulfonatocalix[n]arenes bearing alkyl chains at the lower rim was investigated by NMR spectroscopy and electrical conductivity. The critical micelle concentration was determined, and the tendency of this special class of surfactants to self-aggregate in aqueous solution was analyzed as a function of the alkyl chain length and the number of aromatic units in the macrocyclic ring. The structure of the surfactants in the monomeric and micellized states was elucidated by means of 1H NMR and, in the case of the calix[6]arene derivative, with 2D NMR experiments. While all amphiphilic calix[4]arenes studied here are blocked in the cone conformation, in the monomeric state the calix[6]arene adopts a pseudo-1,2,3-alternate conformation and the calix[8]arene is conformationally mobile. These calixarenes undergo an aggregation-induced conformational change, adopting the cone conformation in the micelles. The structure and size of the aggregates were studied by diffusion ordered spectroscopy (DOSY) experiments, and the results indicate that these surfactants self-assemble into ellipsoidal micelles. © 2012 American Chemical Society.

Senis Y.,University of Birmingham | Garcia A.,University of Santiago de Compostela
Methods in Molecular Biology | Year: 2012

Platelets pose unique challenges to cell biologists due to their lack of nucleus and low levels of messenger RNA. Platelets cannot be cultured in great abundance or manipulated using common recombinant DNA technologies. As a result, platelet research has lagged behind that of nucleated cells. The advent of mass spectrometry and its application to protein biochemistry brought with it great hopes for the platelet community that are now being realized. This technology is ideally suited for identifying low-abundance proteins, protein-protein interactions, and post-translational modifications in complex protein mixtures. Over the past 10 years, proteomics has delivered in many ways, providing platelet biologists with a comprehensive list of proteins expressed in platelets, information on post-translational modifications, protein interactions and sub-cellular localization. Several novel and important platelet membrane proteins, including CLEC-2, CD148, G6b-B, G6f, and Hsp47, have been identified using proteomics-based approaches. New, more sensitive instrumentation and novel approaches are making it increasingly possible to identify ever lower amounts of proteins. In this chapter we highlight some of the major achievements of platelet proteomics to date, discussing challenges and how they were overcome. We also discuss new frontiers and applications of proteomics to platelets and microparticles in health and disease, as we strive to better understand the molecular mechanisms underlying the platelet response to vascular injury. © 2012 Springer Science+Business Media, LLC.

Noguera J.C.,University of Vigo | Lores M.,University of Santiago de Compostela | Alonso-Alvarez C.,Institute Investigacion en Recursos Cinegeticos | Velando A.,University of Vigo
Functional Ecology | Year: 2011

1.Conditions during early stages of life may have an important effect on phenotype, by inducing programmed responses that may remain throughout the lifetime of an animal. One very important factor that can promote long-term changes in phenotype is restriction of food intake (dietary restriction, DR). 2.Recently, it has been shown that DR may induce an increase in antioxidant and repair mechanisms as a result of hormetic responses. Interestingly, the induction of antioxidant and repair mechanisms may be triggered by transitory increases in reactive oxygen species. Dietary-derived antioxidants, such as vitamin E, may be important to determine the compensatory effect of DR. 3.To investigate the effect of DR on attenuation of oxidative damage, we manipulated dietary intake (by restricting food ingestion) and antioxidant availability (by vitamin E supplementation) during the first days of life of yellow-legged gull (Larus michahellis) chicks. We then measured oxidative status and body mass during the early development of chicks. 4.We found that an early short event of food shortage strongly affected the oxidative status of the chicks and their growth patterns. We observed less oxidative damage to proteins and DNA in dietary restricted chicks, after the period of food restriction, than in non-restricted chicks. Unexpectedly, vitamin E supplementation did not suppress the hormetic effect of DR, but instead increased it. 5.These novel results support the idea that short events of DR during early development induce a reduction in oxidative damage in wild animals. The results suggest that DR promotes the induction of an early hormetic response in some antioxidant defence processes and/or repair mechanisms. These findings have important implications for our understanding of how early conditions may shape the phenotype of an organism, and also for the study of evolutionary trade-offs during early growth. © 2011 The Authors. Functional Ecology © 2011 British Ecological Society.

Vazquez A.,University of Santiago de Compostela | Iglesias G.,University of Plymouth
Energy | Year: 2015

Tidal stream energy projects are not likely to materialise unless they are proven to be economic. In this work, we present a new geospatial tool to determine the optimum sites for tidal stream energy exploitation based on this fundamental requirement of economic feasibility, and more specifically, on the LCOE (levelised cost of energy): LCOE mapping. The methodology combines numerical model results of the resource with economic assessments in a Matlab-based tool designed ad hoc. Thus, not only the spatial variability of the resource but also its all-important temporal variability is considered. In particular, the energy density is obtained by means of numerical integration of the power density throughout a tidal cycle. The new tool allows for considering the diameter and power curve of the specific turbines, too. As a case study, the method is applied to the Bristol Channel and Severn Estuary (UK), one of the most promising areas for tidal stream exploitation in the UK. Additionally, a sensitivity analysis is performed and thus, cost trends are analysed. In summary, the LCOE map constitutes a new tool to assess tidal stream sites in an area of interest based on a fundamental economic parameter of an energy project: the LCOE. © 2015 Elsevier Ltd.

Campos R.P.,ISJD S | Vazquez M.I.,University of Santiago de Compostela
Rheumatology International | Year: 2013

Previous studies show controversial results regarding the influence of age on health-related quality of life (HRQOL) in patients with Fibromyalgia (FM). While some studies suggest that elderly patients have a worse HRQOL when compared with younger patients, others did not find differences according to age. The aim of the study was to analyse the impact of FM on HRQOL as far as patients' age is concerned. A cross-sectional study was conducted with 76 adult Portuguese women with FM between 22 and 75 years ($$ \bar{x} = 4 9. 6 1 $$; SD = 10.07). The HRQOL was assessed through the generic questionnaire Short-Form 36 Health Survey (SF-36). To this study, we considered the direct scores on each dimension that encompasses the SF-36, and standardized scores of each dimension by age and gender, using Portuguese normative data. Data regarding clinical and psychological variables (anxiety, depression and social support) were also collected. Of the total sample, 11 patients (14.5 %) had <39 years, 54 patients (71 %) had between 40 and 59 years and 11 subjects (14.5 %) had 60 years or more. There were no differences between the three patient groups in any of the clinical and psychological variables considered, and the same lack of differences was observed in the SF-36 direct scores. Nevertheless, when the analysis was made using the SF-36 standardized scores, the patients over 60 years presented a significantly lower deterioration on physical (Physical Function, Role Physical and General Health) and social dimensions when compared with patients under 59 years, on Vitality when compared with patients under 39 years, and on Body Pain when compared to patients with age between 40 and 59 years. Regarding mental dimensions, no differences were found in the three age groups. In conclusion, it is important to control age effect on HRQOL to determine the specific impact of FM. Controlling the age effect on the HRQOL with standardized scores, elderly women with FM (≥60 years) have less impact of the disease on the physical and social dimensions of the HRQOL than younger patients. © 2012 Springer-Verlag Berlin Heidelberg.

Carinena P.,University of Santiago de Compostela
Wiley Interdisciplinary Reviews: Data Mining and Knowledge Discovery | Year: 2014

Data mining for association rules aims to discover interesting relationships among sets of items in a database. Very often these databases include some kind of temporal information, the most common being a temporal label indicating transaction date. Within the field of association rule mining temporal information has been used to obtain sequential association rules, periodic or cyclic association rules, calendric association rules, or event-driven association rules. The temporal component is also relevant when analyzing how association rules evolve if datasets are evaluated on different time-slices. On the other hand, in traditional association rules item attributes were usually Boolean, but many attributes in current databases are quantitative in nature. Fuzzy temporal association rules arise from the use of fuzzy sets to describe quantitative temporal and/or not temporal attributes of items in a database, and/or to introduce fuzzy temporal specifications for the rules a user is interested in; the use of fuzzy sets allows a linguistic interpretation of the rules and also provides means to handle the uncertainty present in attribute measurements. Depending on the rule pattern the final user is interested in, different methods for fuzzy temporal association rule mining can be found in the literature, with mining algorithms adapted to the rule model being used. © 2013 John Wiley & Sons, Ltd.

Faustino C.M.C.,University of Lisbon | Calado A.R.T.,University of Lisbon | Garcia-Rio L.,University of Santiago de Compostela
Journal of Colloid and Interface Science | Year: 2011

The mixed micelle formation in aqueous solutions between an anionic gemini surfactant derived from the amino acid cystine (C 8Cys) 2, and the phospholipids 1,2-diheptanoyl-sn-glycero-3-phosphocholine (DHPC, a micelle-forming phospholipid) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC, a vesicle-forming phospholipid) has been studied by conductivity and the results compared with the ones obtained for the mixed systems with the single-chain surfactant derived from cysteine, C 8Cys. Phospholipid-surfactant interactions were found to be synergistic in nature and dependent on the type of phospholipid and on surfactant hydrophobicity. Regular solution theory was used to analyse the gemini surfactant-DHPC binary mixtures and the interaction parameter, β 12, has been evaluated, as well as mixed micelle composition. The results have been interpreted in terms of the interplay between reduction of the electrostatic repulsions among the ionic head groups of the surfactants and steric hindrances arising from incorporation of the zwitterionic phospholipids in the mixed micelles. © 2011 Elsevier Inc.

Martins R.B.,Piaget Institute | Martins R.B.,Piaget Alimentar Unipessoal Lda | Hogg T.,Catholic University of Portugal | Otero J.G.,University of Santiago de Compostela
Food Control | Year: 2012

The aim of this study was to assess the food hygiene knowledge of professional food handlers from an institutional catering company which manufactures and distributes meals to the canteens of schools, kindergartens and nursing homes in Portugal. A total of 101 food handlers from 18 geographically distributed business units were assessed. Data collection employed a previously used, multiple-choice questionnaire, aimed at exploring the food safety knowledge and practices of individual respondents. The average score of questions answered correctly was 13 out of 23 (56.5%) with a standard deviation (SD) of 3.22. However, the percentage of correct answers varies with the issues questioned, being significantly lower on issues such as temperature control (p < 0.001) and sources of contamination/high-risk foods (p < 0.001). The level of knowledge was influenced by the level of formal education (p = 0.025) of respondents. The results reinforce the importance of conducting a preliminary assessment of training needs and evaluating the effectiveness of training. © 2011 Elsevier Ltd.

Blooms of phytoplankton organisms, especially cyanobacteria represent an important economic and ecological problem in the management of water and aquatic ecosystems. The biomass increment, besides causing sthetic problems, such as the appearance of foams and odors, alters the taste of drinking water and causes deoxygenation and water chemistry changes when it decomposes compromising the survival of aquatic organisms. However, blooms of cyanobacteria are the most studied and known as these organisms produce bioactive metabolites (cyanotoxins) that constitute a serious environmental problem with serious implications on human and animal health. Therefore, the need to resolve the problems associated with cyanobacteria has led to the use of multiple techniques to alleviate their uncontrolled development and improve water quality. This paper is a review of methods for cyanobacterial blooms control in inland waters. All these techniques are related to the factors that regulate the primary production. Thus, the reduction of the external phosphorus loading is sought through the control of inputs in the watershed (agriculture, sanitation, industry, etc.), but also by acting directly on the water body. Moreover, within this intervention strategy on the primary factors controlling the growth of autotrophs, techniques to limit the incident light have also been developed. Mechanical control has been addressed by physical removal of the biomass of cyanobacteria, application of ultrasounds, etc. For the chemical controls a variety of compounds with very different effects, ranging from the application of algcides or herbicides to oxidants and other substances such as Cu, MnO4K2, H2O2, etc. have been used. Simultaneously, a large number of agents for biological control have been tested with varying success (e.g. viruses, bacteria, protozoa, fungi, aquatic plants, fish) and plant materials in robic decomposition have been widely used. © Asociación Ibérica de Limnología Madrid.

Forests and tourism: Forest tourism in Galicia This paper examines the main characteristics of the tourism sector in Galicia today and analyzes the special features of a particular type of tourism: forest tourism. The aim is to highlight that forest tourism is an activity which affords many opportunities for development in Galicia and can function as both a catalyst for certain rural areas and a complement to other tourism activities that have already been developed in Galicia. To achieve this objective, the distribution and characteristics of forests and their relation to the territorial distribution of other types of tourism, such as rural tourism or ecotourism, are analyzed. © 2016, Universitat Autonoma de Barcelona. All rights reserved.

Schellekens J.,University of Santiago de Compostela | Buurman P.,Wageningen University
Geoderma | Year: 2011

n-Alkane distributions are frequently used as palaeoclimate proxies in ombrotrophic peat deposits. Although n-alkane distributions differ strongly between plant species, n-alkanes are not species-specific molecules. For a proper interpretation, it is important to understand the different abundances of n-alkanes in various plant species as well as the changes that occur when plant litter is transformed to peat. In particular because molecular markers are especially valuable in highly decomposed peat where plant remains are no longer recognizable, it is important to understand the effects of decomposition on n-alkane distributions.The organic matter (OM) of a high-resolution sampled, 9m thick, ombrotrophic peat deposit from Tierra del Fuego was analysed with pyrolysis-gas chromatography/mass spectrometry (pyrolysis-GC/MS). The same samples were analysed for carbon (C) and nitrogen (N) content. Depth profiles of C:N ratio, the summed lignin and summed polysaccharide pyrolysis products, and markers specific for Sphagnum spp., Empetrum rubrum and Nothofagus antarctica, enabled a reconstruction of changes in vegetation composition to be made. This reconstruction was used to examine the validity of the n-C 23 alkane to indicate Sphagnum and the summed long chain n-alkanes (C 29 and C 31) to reflect leaf input of the woody species E. rubrum and N. antarctica.Our results show that even in Sphagnum-dominated peat, the n-alkane distribution is not determined by Sphagnum but by leaf input of E. rubrum and N. antarctica. However, good correlations between the n-C 23 alkane and the Sphagnum marker 4-isopropenylphenol, and between the summed n-C 29 and n-C 31 alkanes and the marker of N. antarctica support that their relative change with depth can be used to indicate the abundance of these species in Sphagnum-dominated peat. In peat with relatively low contributions of Sphagnum, both n-alkane proxies (C 23 and C 29+C 31) reflect the degree of decomposition. We evaluated the influence of Sphagnum dominance, decomposition, and pyrolysis on the n-alkane distributions in peat OM. © 2011 Elsevier B.V.

Fagundez J.,University of La Coruna | Izco J.,University of Santiago de Compostela
International Journal of Geographical Information Science | Year: 2016

We explore the use of toponyms as an information source of land use changes in heathland landscapes of Galicia, an Atlantic region of northwest Spain. Heathlands are prized for their condition of remarkable landscapes, biodiversity reservoirs and cultural heritage areas. A strong decline of heathland cover has taken place in Atlantic Europe during the last centuries, as land use changes toward more productive systems. Galicia retains a high proportion of heathland cover, but there is a trend of land use transformation to forest plantations and improved pastures. Place names rooted with vernacular names of heathers (Erica, Calluna and Daboecia genera, Ericaceae) were recorded in a geo-referenced database. We applied spatial statistics to account for correlation between heath toponym density and present-day heathland distribution. We did not find such correlation, but differences were found for altitudinal ranks, suggesting a wider habitat loss at lowlands than at mountain areas. We discuss the possibilities of a systematic use of toponymic databases in historical landscape reconstruction. © 2015 Taylor & Francis.

Paul V.,University of Santiago de Compostela | McKenzie F.H.,Curtin University Australia
Land Use Policy | Year: 2013

There has been a growing literature on alternative food networks (AFNs); structures that reconfigure the systems of production, distribution and consumption of food. Part of this literature emphasises the local scale and the idea of proximity. In a world that is increasingly urban, AFNs at a local scale can be more easily developed by linking peri-urban farmlands and cities. However, agriculture in the rural-urban fringe struggles to survive in the face of urban pressures and sprawl; a process which undermines viable agricultural production in the city's countryside. A widely used strategy to address these pressures has been farmland protection, undertaken in different ways depending on the legal framework of particular countries. This paper considers farmland conservation and AFNs development issues through a case-study of the Baix Llobregat Agricultural Park (BLAP) in metropolitan Barcelona. It concludes that AFNs in peri-urban areas are only possible if farmland preservation is guaranteed, and that the former does not come as a direct consequence of the latter. The specific conditions in which both can occur will be of interest for scholars as well as policy-makers and planners. © 2012 Elsevier Ltd.

Ferreiro E.G.,University of Santiago de Compostela
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2015

Recent results from proton(deuteron)-nucleus collisions at RHIC and LHC energies have shown an unexpected suppression of excited quarkonium states as compared to their ground states. In particular, stronger suppression of the ψ(2. S) relative to the J/ψ has been detected. Similar observations were made at lower energies and were easily explained by nuclear absorption. At higher energies, a similar explanation would violate the Heisenberg principle, since the calculations based on the uncertainty principle lead to a charmonium formation time expected to be larger than the nuclear radius, which results in identical nuclear break-up probability for the ψ(2. S) and J/ψ. On the contrary, this behavior is naturally explained by the interactions of the quarkonium states with a comoving medium. We present our results on J/ψ and ψ(2. S) production for d. +. Au collisions at s=200 GeV and for p. +. Pb collisions at s=5.02 TeV. © 2015 The Author.

Dominguez Munoz J.E.,University of Santiago de Compostela
Best Practice and Research: Clinical Gastroenterology | Year: 2010

The diagnosis of chronic pancreatitis is mainly based on imaging procedures (e.g., endoscopic ultrasound, magnetic resonance cholangiopancreatography (MRCP) and magnetic resonance imaging (MRI)). Functional testing in this context could however be still of help in cases of inconclusive morphological findings. With this aim, only the secretin-pancreozymin test and the endoscopic test are sensitive enough. The role of other function tests, such as the quantification of the coefficient of fat absorption (CFA) and the 13C-mixed triglyceride breath test, is limited to the diagnosis of exocrine pancreatic insufficiency with maldigestion. Faecal elastase and chymotrypsin are still useful for detecting reduction of pancreatic secretion in patients with different pancreatic diseases and patients' compliance to enzyme replacement therapy, respectively. Other tests used in the past (e.g., Lundh test, N-benzoyl-tryosyl para-aminobenzoic acid (NBT-PABA) test, pancreolauryl test and amino acid consumption test) are neither available now nor useful for clinical practice. This article reviews the different pancreatic function tests commercially available and their role in clinical practice. © 2010 Elsevier Ltd. All rights reserved.

Soengas R.G.,University of La Coruna | Estevez A.M.,University of Santiago de Compostela
European Journal of Organic Chemistry | Year: 2010

A novel method for the preparation of 2-nitroalkan-1-ols by an indium-promoted reaction of bromonitromethane with a variety of aldehydes is reported. The reaction was also performed with 2-bromo-2-nitropropanes to afford 2,2-dialkyl-2-nitroalkan-1-ols. The use of chiral sugar-derived aldehydes furnished the corresponding 2-nitroalkan-1-ols with excellent stereoselectivity. The utility of the novel sugar-derived 2,2-dialkyl-2-nitroalkan-1-ols for the preparation of branched iminosugar derivatives was demonstrated by the preparation of a hydroxymethyl branched polyhydroxylated azepane. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chen F.,Xiangnan University | Nieto J.J.,University of Santiago de Compostela | Zhou Y.,Xiangtan University
Nonlinear Analysis: Real World Applications | Year: 2012

We present some results for the global attractivity of solutions for fractional differential equations involving RiemannLiouville fractional calculus. The results are obtained by employing Krasnoselskii's fixed point theorem. Similar results for fractional differential equations involving Caputo fractional derivative are also obtained by using the classical Schauder's fixed point theorem. Several examples are given to illustrate our main results. © 2011 Elsevier Ltd. All rights reserved.

Carballido-Landeira J.,Free University of Colombia | Trevelyan P.M.J.,University of Santiago de Compostela | Almarcha C.,University of South Wales | De Wit A.,IRPHE
Physics of Fluids | Year: 2013

In a gravitational field, a horizontal interface between two miscible fluids can be buoyantly unstable because of double diffusive effects or because of a Rayleigh-Taylor instability arising when a denser fluid lies on top of a less dense one. We show here both experimentally and theoretically that, besides such classical buoyancy-driven instabilities, a new mixed mode dynamics exists when these two instabilities act cooperatively. This is the case when the upper denser solution contains a solute A, which diffuses sufficiently faster than a solute B initially in the lower layer to yield non-monotonic density profiles after contact of the two solutions. We derive parameter plane, where R is the buoyancy ratio between the two solutions and δ is the ratio of diffusion coefficient of the solutes. We find an excellent agreement of these theoretical predictions with experiments performed in Hele-Shaw cells and with numerical simulations. © 2013 American Institute of Physics.

Feas X.,University of Santiago de Compostela | Estevinho M.L.,Polytechnic Institute of Braganca
Journal of Medicinal Food | Year: 2011

Monofloral heather (Erica sp.) honey samples (n=89), harvested in Portugal according to European organic beekeeping rules, were analyzed to test their antifungal effect against Candida albicans, Candida krusei, and Cryptococcus neoformans. A synthetic honey solution was also tested to determine antifungal activity attributable to sugars. The specific growth rate (μ) values showed that growth of all the yeasts was reduced in the presence of honey. The honey concentration (% wt/vol) that inhibited 10% of the yeast growth (X min) was 13.5% for C. albicans, 20.5% for C. krusei, and 17.1% for C. neoformans. The respective concentrations of heather honey and synthetic honey in the C. krusei culture medium above 60% (wt/vol) that inhibited 90% of the yeast growth (X max) and X min, respectively, were established, whereas C. albicans and C. neoformans were more resistant because X max values were not reached over the range tested (10-60%, wt/vol). Heather honey might be tapped as a natural resource to look for new medicines for the treatment of mycotic infections. Further studies are now required to demonstrate if this antifungal activity has any clinical application. © 2011 Mary Ann Liebert, Inc.

Astariz S.,University of Santiago de Compostela | Perez-Collazo C.,University of Plymouth | Abanades J.,University of Plymouth | Iglesias G.,University of Plymouth
Energy | Year: 2015

The cost competitiveness of wave energy must be enhanced if it is to become a viable alternative to fossil fuels. This can be achieved by realising the synergies between wave and offshore wind energy through co-located wind turbines and WECs (Wave Energy Converters). First, by using the infrastructure of the wind farm the WECs will be less costly to install and maintain. Second, by deploying the WECs along the periphery of the farm a milder wave climate (shadow effect) will ensue within the farm and result in reduced structural loads and enlarged weather windows for Operation & Maintenance. The objective of this work is to investigate the optimum layout for the co-located wind-wave farm with a view to maximising these benefits. This investigation is carried out through a case study: an offshore wind farm consisting of 80 turbines in the Wave Hub area (SW England). To analyse the influence of the farm layout, high-resolution numerical modelling is used, and no fewer than 14 different layouts are compared. We find that the layout does play a fundamental role and that reductions of up to 40% in the significant wave height can be achieved - or up to 64% in terms of energy density. © 2015 Elsevier Ltd.

Baranowska A.,Nicolaus Copernicus University | Baranowska A.,University of Santiago de Compostela | Sadlej A.J.,Nicolaus Copernicus University
Journal of Computational Chemistry | Year: 2010

We report on the development and testing of large polarized basis sets (LPolX, where X is the element symbol) for accurate calculations of linear and nonlinear electric properties of molecules. The method used to generate LPolX sets is based on our studies of the analytic dependence of Gaussian functions on external time-independent and time-dependent electric fields. At variance with the earlier investigations of small, highly compact (ZPolX) basis sets for moderately accurate calculations of electric properties of large molecules, the present goal is to obtain basis sets that are nearly saturated with respect to the selected class of electric properties and can be used for accurate studies of interaction-induced properties. This saturation makes the LPolX sets also useful in calculations of optical properties for chiral molecules. In this article, the LPolX sets are generated for X = H, C, N, O, and F, and examined in calculations of linear and nonlinear electric properties of four standard test systems: HF, N 2, CO, and HCN. The study of the performance of LPolX basis sets has been carried out at different levels of approximation ranging from the SCF HF method to highly correlated CCSD(T) approach. The results obtained in this study compare favorably with accurate reference data and show a high level of saturation of LPolX basis sets with respect to the polarization effect due to external electric fields. © 2009 Wiley Periodicals, Inc.

Alonso-Meijide J.M.,University of Santiago de Compostela | Freixas J.,Polytechnic University of Catalonia
Decision Support Systems | Year: 2010

In this paper we propose a new power index useful for the evaluation of each member in a committee, or democratic institution, and the degree of influence over the voting decision making system. The proposed solution is based on the observation that democratic organizations not only tend to form coalitions which can by themselves guarantee the control of the organization, but that they also do it in an extremely efficient way that avoids the inclusion of powerful members if they can be replaced by weaker ones. The mathematical foundation of the new measure is based on two different axiomatizations. A comparison with other well-known measures is also done. © 2010 Elsevier B.V. All rights reserved.

Ferreiro E.G.,University of Santiago de Compostela | Fleuret F.,Ecole Polytechnique - Palaiseau | Lansberg J.P.,University Paris - Sud | Rakotozafindrabe A.,CEA Saclay Nuclear Research Center
Physical Review C - Nuclear Physics | Year: 2013

Based on our previous studies, we predict the nuclear-matter effects on J/ψ production in proton-nucleus collisions for the recent Large Hadron Collider pPb runs at √sNN=5 TeV. We have analyzed the effects of the modification of the gluon parton distribution functions in the nucleus, using an exact kinematics for a 2→2 process, namely, g+g→J/ψ+g as expected from leading-order perturbative QCD. This allows us to constrain the transverse-momentum while computing the nuclear modification factor for different rapidities, unlike with the usual simplified kinematics. Owing to the absence of measurement in pp collisions at the same √sNN and owing to the expected significant uncertainties in yield interpolations which would hinder definite interpretations of the nuclear modification factor R pPb, we have derived forward-to-backward and central-to-peripheral yield ratios in which the unknown proton-proton yield cancels. These have been computed without and with a transverse-momentum cut, e.g., to comply with the ATLAS and CMS constraints in the central-rapidity region. © 2013 American Physical Society.

Conde E.,University of Santiago de Compostela | Gaillard J.,University of Swansea
Nuclear Physics B | Year: 2011

We study the addition of Nf flavor D5-branes to supergravity solutions describing D5-branes wrapping two-cycles of genus g>1 inside a six-dimensional space equipped with an SU(3)-structure. The non-zero genus g on the gravity side is dual to the existence of massless adjoint chiral superfields. Three types of internal manifolds are considered, each involving one of the following fibered products: H2×SL̃2, S2×SL̃2 or H2×S3, where SL̃2 stands for the universal cover of SL(2,R). For the first one, we investigate the dual field theories. We show that some of the solutions with Nf≠0 are dual to four-dimensional N=1 field theories exhibiting a Kutasov-like duality taking Nc→kNf-Nc and keeping Nf fixed. Computed from the supergravity picture, k is in general a rational number, which can be made integer to fit the expectation from the field theory side. We finally study some other properties of those field theories. © 2011 Elsevier B.V.

Casalderrey-Solana J.,University of Barcelona | Mehtar-Tani Y.,CEA Saclay Nuclear Research Center | Salgado C.A.,University of Santiago de Compostela | Tywoniuk K.,Lund University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

We propose a new description of the jet quenching phenomenon observed in nuclear collisions at high energies in which coherent parton branching plays a central role. This picture is based on the appearance of a dynamically generated scale, the jet resolution scale, which controls the transverse resolution power of the medium to simultaneously propagating color probes. Since from the point of view of the medium all partonic jet fragments within this transverse distance act coherently as a single emitter, this scale allows us to rearrange the jet shower into effective emitters. We observe that in the kinematic regime of the LHC, the corresponding characteristic angle is comparable to the typical opening angle of high-energy jets such that most of the jet energy is contained within a non-resolvable color coherent inner core. Thus, a sizable fraction of the jets is unresolved, losing energy as a single parton without modifications of their intra-jet structure. © 2013 Elsevier B.V.

Acosta E.,University of Santiago de Compostela | Sasian J.,University of Arizona
Optics Express | Year: 2011

We discuss a set of phase plate-pairs for the generation of variable amounts of primary spherical aberration. The surface descriptions of these optical plates are provided, and their aberration-generating properties are verified with real ray-tracing. These plate-pairs are robust in that they allow large tolerances to spacing as well as errors in the relative displacement of the plates. Both primary spherical aberration (r4) and Zernike spherical aberration (6r4- 6r2 + 1) can be generated. The amount of spherical aberration is proportional to the plate-pair displacement and in our example it reaches up to 48 waves (̃8 waves Zernike) for a clear aperture of 25 mm. © 2011 Optical Society of America.

Veigas M.,University of Santiago de Compostela | Iglesias G.,University of Plymouth
International Journal of Green Energy | Year: 2015

The Spanish Canary Island of Tenerife, owing to the isolation of its electricity grid and its status as a UNESCO Biosphere Reserve, aims to become energy self-sufficient and reduce its carbon footprint. With these goals in view, renewable energy sources, in particular wave and offshore wind, are promoted to satisfy the energy needs of the island. The main objective of this work is to analyse the energy that could be obtained from a hybrid wave-wind farm located in an optimum area for the exploitation of both resources. Such a farm, consisting of offshore wind turbines and co-located Wave Energy Converters (WECs), would realise the synergies between wave and offshore wind energy. Data from a hindcast database spanning 44 years are used, and the seasonal variability of the hybrid farms output is investigated. It is found that the hybrid farm does constitute an excellent approach to satisfying the energy requirements of Tenerife, and that most of the wave and offshore wind energy will be produced in summer mainly because of the high occurrence of winds and waves in the ranges for which offshore wind turbines and WECs are most efficient. Copyright © 2015 Taylor & Francis Group, LLC.

Astariz S.,University of Santiago de Compostela | Perez-Collazo C.,University of Plymouth | Abanades J.,University of Plymouth | Iglesias G.,University of Plymouth
Energy Conversion and Management | Year: 2015

Operation and maintenance can jeopardise the financial viability of an offshore wind energy project due to the cost of downtime, repairs and, above all, the inevitable uncertainties. The variability of wave climate can impede or hinder emergency repairs when a failure occurs, and the resulting delays imply additional costs which ultimately reduce the competitiveness of offshore wind energy as an alternative to fossil fuels. Co-located wind turbines and Wave Energy Converters (WECs) are proposed in this paper as a novel solution: the reduction of the significant wave height brought about by the WECs along the periphery of the wind farm results in a milder wave climate within the farm. This reduction, also called shadow effect, enlarges weather windows for Operation & Maintenance (O&M). The objective of this paper is to investigate the increase in the accessibility time to the turbines and to optimise the layout for the co-located wind-wave farm in order to maximise this time. The investigation is carried out through a case study: Alpha Ventus, an operating offshore wind farm. To maximise the reduction of wave height in the turbine area no fewer than 15 layouts are tested using high-resolution numerical modelling, and a sensitivity analysis is conducted. The results show that, thanks to the wave energy extraction by the WECs, weather windows (access time) can increase very significantly - over 80%. This substantial effect, together with other benefits from the combination of wave and offshore wind power in a co-located farm (common electrical infrastructures, shared O&M equipment and crews, etc.) will enhance the economic viability of these marine renewables, and hence their potential to reduce our carbon footprint on the planet. © 2014 Elsevier Ltd. All rights reserved.

dos Santos C.,University of Porto | dos Santos C.,University of Santiago de Compostela | da Hora E.,Federal University of Paraiba
European Physical Journal C | Year: 2011

In this paper we study one-dimensional static self-dual non-topological solitons in an Abelian-Higgs Chern-Simons model with a non-canonical kinetic term. We choose a scalar potential with a single minimum and present an analytical soliton solution which corresponds to an electrically charged lump-like soliton without total momentum and located in a region where the scalar field gets maximum. The solitonic boundary conditions impose a discontinuity on the electric field across the soliton line where, then, there is a linear charge density. © Springer-Verlag/Società Italiana di Fisica 2011.

Reboredo J.C.,University of Santiago de Compostela
Energy Economics | Year: 2015

We study systemic risk and dependence between oil and renewable energy markets using copulas to characterize the dependence structure and to compute the conditional value-at-risk as a measure of systemic risk. We found significant time-varying average and symmetric tail dependence between oil returns and several global and sectoral renewable energy indices. Our evidence on systemic risk indicates that oil price dynamics significantly contributes around 30% to downside and upside risk of renewable energy companies. These results have important implications for risk management and renewable energy policies. © 2014 Elsevier B.V.

Llaneza L.,S.L. Perpetuo Socorro no 12 Entresuelo | Llaneza L.,University of Santiago de Compostela | Lopez-Bao J.V.,S.L. Perpetuo Socorro no 12 Entresuelo | Lopez-Bao J.V.,CSIC - Donana Biological Station | Sazatornil V.,S.L. Perpetuo Socorro no 12 Entresuelo
Diversity and Distributions | Year: 2012

Aim Understanding which human or environmental factors interact to enable or to limit the occurrence and persistence of large carnivores in human-dominated landscapes is an important issue for their effective conservation, especially under the current scenario of global change where most of their former habitat is being transformed by humans. Location NW Iberian Peninsula. Methods We combine data on the distribution of Iberian wolves (Canis lupus signatus) living in a human-dominated landscape in NW Spain and variation and partitioning methods to investigate the relative importance of three groups of predictors: food availability, humans and landscape attributes - each group expected to have unequal effects on wolf reproduction and survival - and their interactions on the occurrence of this species. Results We found that the group of predictors related with landscape attributes (altitude, roughness and refuge) strongly determined wolf occurrence, followed by humans and food availability. Variance partitioning analysis revealed that the three most important components determining wolf occurrence were related with landscape attributes: (1) the joint effects of the three predictor groups, (2) the joint effect of humans and landscape attributes and (3) the pure effect of landscape attributes. Altitude had the main independent contribution to explain the probability of wolf occurrence. Main conclusions In human-dominated landscapes, the occurrence of wolves is the result of a complex interaction among several environmental and human factors. Our results suggest that the characteristics of the landscape (spatial context) - factors associated with the security of wolves facilitating that animals go unnoticed by humans, wolf movements, dispersal events and short-time colonization - become more important in human-dominated landscapes and may have played a key role in the occurrence and persistence of this species throughout decades modulating the relationship between humans and wolf distribution. © 2011 Blackwell Publishing Ltd.

Gomez-Brandon M.,University of Vigo | Aira M.,University of Vigo | Lores M.,University of Santiago de Compostela | Dominguez J.,University of Vigo
Bioresource Technology | Year: 2011

Most studies investigating the effects of earthworms on microorganisms have focused on the changes before and after vermicomposting rather than those that occur throughout the process. In the present study, we designed continuous feeding reactors in which new layers of pig slurry (1.5 and 3. kg) were added sequentially to form an age gradient inside the reactors in order to evaluate the impact of the earthworm species Eisenia fetida on microbial community structure and function. The activity of earthworms greatly reduced the bacterial and fungal biomass and microbial diversity relative to the control values. However, the pronounced presence of earthworms in the younger layers stimulated microbial activity and as such increased carbon mineralization probably due to the fact that the microorganisms may have been less resource-limited as a result of earthworm activity, as indicated by the ratio of monounsaturated to saturated PLFAs. © 2010 Elsevier Ltd.

Gorter S.L.,Maastricht University | Bijlsma J.W.,University Utrecht | Cutolo M.,University of Genoa | Gomez-Reino J.,University of Santiago de Compostela | And 2 more authors.
Annals of the Rheumatic Diseases | Year: 2010

Glucocorticoids (GCs) rapidly reduce disease activity in early and advanced rheumatoid arthritis (RA). This systematic review on behalf of the task force on recommendations for the management of RA addresses the efficacy of GCs in RA. A literature search was performed in Medline, Embase, the Cochrane database, and the ACR/EULAR abstracts 2007 and 2008 on a set of questions relating to the use of GCs in RA. Eleven publications (including three Cochrane reviews comprising 33 trials) that met the criteria for detailed assessment were found. Robust evidence that GCs are effective as bridging therapy was obtained. The addition of GCs, to either standard synthetic disease-modifying antirheumatic drug (DMARD) monotherapy or combinations of synthetic DMARDs, yields clinical benefits and inhibition of radiographic progression that may extend over many years. In early RA, the addition of low-dose GCs (<7.5 mg/day) to DMARDs leads to a reduction in radiographic progression; in longstanding RA, GCs (up to 15 mg/day) improve disease activity. There is some evidence that appropriate timing of GC administration may result in less morning stiffness. Only indirect information was found on the best tapering strategy, supporting the general view that GCs should be tapered slowly in order to avoid clinical relapses. GCs are effective in relieving signs and symptoms and inhibiting radiographic progression, either as monotherapy or in combination with synthetic DMARD monotherapy or combination therapy.

Fan Y.,Rutgers University | Miguez-Macho G.,University of Santiago de Compostela
Hydrology and Earth System Sciences | Year: 2010

Climate and land ecosystem models simulate a dry-season vegetation stress in the Amazon forest, but observations do not support these results, indicating adequate water supply. Proposed mechanisms include larger soil water store and deeper roots in nature and the ability of roots to move water up and down (hydraulic redistribution), both absent in the models. Here we provide a first-order assessment of the potential importance of the upward soil water flux from the groundwater driven by capillarity. We present a map of equilibrium water table depth from available observations and a groundwater model simulation constrained by these observations. We then present a map of maximum capillary flux these water table depths, combined with the fine-textured soils in the Amazon, can potentially support. The maps show that the water table beneath the Amazon can be shallow in lowlands and river valleys (<5 m in 36% and <10 m in 60% of Amazonia). These water table depths can potentially accommodate a maximum capillary flux of 2.1 mm day'1 to the land surface averaged over Amazonia, but varies from 0.6 to 3.7 mm day'1 across nine study sites. We note that the results presented here are based on limited observations and simple equilibrium model calculations, and as such, have important limitations and must be interpreted accordingly. The potential capillary fluxes are not indicative of their contribution to the actual evapotranspiration, and they are only an assessment of the possible rate at which this flux can occur, to illustrate the power of soil capillary force acting on a shallow water table in fine textured soils. They may over-estimate the actual flux where the surface soils remain moist. Their contribution to the actual evapotranspiration can only be assessed through fully coupled model simulation of the dynamic feedbacks between soil water and groundwater with sub-daily climate forcing. The equilibrium water table obtained here serves as the initial state for the dynamic simulation, and together with the equilibrium potential capillary flux, will serve as a baseline to evaluate the diurnal, event, seasonal and inter-annual dynamics. © 2010 Author(s).

Alvarez-Mozos M.,University of Santiago de Compostela | Tejada O.,University of Barcelona
Decision Support Systems | Year: 2011

We present parallel characterizations of two different values in the framework of restricted cooperation games. The restrictions are introduced as a finite sequence of partitions defined on the player set, each of them being coarser than the previous one, hence forming a structure of different levels of a priori unions. On the one hand, we consider a value first introduced in Ref. [18], which extends the Shapley value to games with different levels of a priori unions. On the other hand, we introduce another solution for the same type of games, which extends the Banzhaf value in the same manner. We characterize these two values using logically comparable properties. © 2011 Elsevier B.V. All rights reserved.

Rodriguez-Rellan C.,University of Santiago de Compostela
Quaternary International | Year: 2016

The Equotip Hardness Tester is applied to different types of quartz and other lithic raw materials in order to determine if variations in the rebound hardness measured by this device may serve as a proxy for detecting the levels of continuity and isotropy of toolstones. Continuity, the amount of cracks and other internal defects; and isotropy, the measure of the directional properties of a raw material, are known to have important effects on the level of consistency and predictability of fractures, which in turn is traditionally considered a main factor for defining the flaking quality of a given raw material.The results demonstrate the existence of differences among the raw materials analysed in both the average value and the variability of the rebound hardness. While cryptocrystalline samples show the most homogeneous results, quartz and metamorphic rocks display a comparatively higher variance. In the specific case of quartz, such variability seems to be mainly caused by the presence of internal planes and discontinuities, while anisotropy, although also active, had played a comparatively modest role. The results achieved by the Equotip Hardness Tester suggest that this device could be successfully used for a basic or preliminary estimating of some of the physical and mechanical properties of stone raw materials. Therefore, it is a potential index test for complementing other, more accurate, laboratory methods. © 2016 Elsevier Ltd and INQUA.

Ojea E.,Basque Center For Climate Change 3 | Loureiro M.L.,University of Santiago de Compostela
Marine Policy | Year: 2010

The current reduction in commercial fish stocks is a problem of global concern. In response to this situation, administrations around the world are attempting to recover critical stocks by implementing new regulations based on catching restrictions and recovery plans. These restrictions have negative effects on local economies, but species recovery also brings important benefits to society in the long term. Given that the recovery of endangered species also results in considerable non-use economic value, this paper employs contingent valuation techniques to measure individual preferences for different recovery levels. We distinguish primarily between existence and option values linked to various levels of the desired stocks and discuss how these values influence willingness to pay (WTP) estimates. Our results show that recovered stocks for hake and Norwegian lobster increase local welfare, and show that the median household WTP is about 17.73€ for a recovery programme regulated by the European Union. © 2009 Elsevier Ltd. All rights reserved.

Adrio L.A.,University of Oviedo | Adrio L.A.,University of Santiago de Compostela | Gimeno J.,University of Oviedo | Vicent C.,Jaume I University
Chemical Communications | Year: 2013

The inexpensive and commercially available catalytic system RuCl 3·nH2O-NaOAc-Zn is active in water for the direct C-H arylation of arenes with aryl/heteroaryl chlorides. The reaction can be accelerated by the use of microwave irradiation and can also be scaled up to a multi-gram scale with excellent isolated yields. © 2013 The Royal Society of Chemistry.

Marquet C.,University of Santiago de Compostela | Marquet C.,CERN | Royon C.,CEA Saclay Nuclear Research Center | Trzebinski M.,Polish Academy of Sciences | Zlebcik R.,Charles University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

The possibility to measure jet-gap-jet final states in double-Pomeron- exchange events at the LHC is presented. In the context of the ATLAS experiment with additional forward physics detectors, cross sections for different experimental settings and gap definitions are estimated. This is done in the framework of the forward physics Monte Carlo interfaced with a perturbative QCD model that successfully reproduces standard jet-gap-jet cross sections at the Tevatron. The extrapolation to LHC energies follows from the Balitsky-Fadin-Kuraev-Lipatov dynamics, implemented in the model at next-to-leading logarithmic accuracy. © 2013 American Physical Society.

Fernandez I.,Complutense University of Madrid | Mascarenas J.L.,University of Santiago de Compostela
Organic and Biomolecular Chemistry | Year: 2012

In this emerging area article, we focus on novel intramolecular transition metal catalysed (4 + 3)-cycloaddition reactions of allenedienes in which the allene acts as an allylic-cation surrogate. This process has emerged as a powerful tool for the construction not only of complex seven-membered rings containing compounds but also different types of useful molecular skeletons by the proper selection of the catalyst. The transformation proceeds with high chemo- and stereoselectivity mainly because it occurs through an exo-like concerted transition state which exhibits a clear in-plane aromatic character. Despite that, different reaction mechanisms (i.e. stepwise processes) are also possible depending on the nucleophilicity of the diene moiety. © 2012 The Royal Society of Chemistry.

dos Santos C.,University of Porto | dos Santos C.,University of Santiago de Compostela | da Hora E.,Federal University of Paraiba
European Physical Journal C | Year: 2010

In this paper we study the structure of one dimensional topological solitons in a generalized Abelian-Higgs Chern-Simons model where the kinetic term is non-canonical. We present an example of an analytical self-dual electrically charged soliton solution which has a finite momentum per unit length along its direction. We compared the physical properties of our soliton with those for wall of Jackiw-Lee-Weinberg wall presented in Jackiw et al. (Phys. Rev. D 42:3488, 1990) to conclude that the non-canonical kinetic term can make the wall "thicker" redistributing uniformly the momentum flow along it. © 2010 Springer-Verlag / Società Italiana di Fisica.

Multivariate covariation matrices occupy a central place in the analysis of evolutionary divergence among populations. They may constrain the multivariate space directions available to the divergence, and at the same time, their structure may be affected by the forces driving the divergence, and may thus provide information about the action of these forces in the past. Unfortunately, the relationship between covariation and divergence is complex and its theoretical analysis has not been completely resolved. To advance in the understanding of this relationship it is therefore necessary to gather information from case studies in which the evolutionary dynamics is as well known as possible. Here I analyse the covariation and divergence in a well-studied hybrid zone of the marine snail Littorina saxatilis. I compare the covariation matrix of seven shell measures with their multivariate divergence both between the two ecotypes in the hybrid zone and among different localities. I also propose an eigenvector-based procedure to predict the multi-character divergence expected under a null model of divergence proportional to within population covariation. The divergence between ecotypes was clearly not proportional to the covariation. Instead, it was in the same direction as the divergent selection pressures estimated in previous studies of this hybrid zone. In addition, the phenotypic divergence between ecotypes, but not between localities, was much larger than expected in terms of Fst estimates already published for this hybrid zone. Finally, I found no evidence of depletion in variance for the traits contributing the most to the divergence. I conclude that the covariation matrix has no direct relationship with the divergence between ecotypes, as it did not seriously constrain the direction of this divergence, nor was influenced in any obvious way by its development in the past. © 2014 Springer International Publishing Switzerland.

Baselga A.,University of Santiago de Compostela
Global Ecology and Biogeography | Year: 2010

Aim: Beta diversity (variation of the species composition of assemblages) may reflect two different phenomena, spatial species turnover and nestedness of assemblages, which result from two antithetic processes, namely species replacement and species loss, respectively. The aim of this paper is to provide a unified framework for the assessment of beta diversity, disentangling the contribution of spatial turnover and nestedness to beta-diversity patterns. Innovation: I derive an additive partitioning of beta diversity that provides the two separate components of spatial turnover and nestedness underlying the total amount of beta diversity. I propose two families of measures of beta diversity for pairwise and multiple-site situations. Each family comprises one measure accounting for all aspects of beta diversity, which is additively decomposed into two measures accounting for the pure spatial turnover and nestedness components, respectively. Finally, I provide a case study using European longhorn beetles to exemplify the relevance of disentangling spatial turnover and nestedness patterns. Main conclusion: Assigning the different beta-diversity patterns to their respective biological phenomena is essential for analysing the causality of the processes underlying biodiversity. Thus, the differentiation of the spatial turnover and nestedness components of beta diversity is crucial for our understanding of central biogeographic, ecological and conservation issues. © 2009 Blackwell Publishing Ltd.

I consider statistical problems in the analysis of multiple-choice food-preference experiments, and propose a univariate analysis of variance design for experiments of this type. I present an example experimental design, for a hypothetical comparison of fruit colour preferences between two frugivorous bird species. In each fictitious trial, four trays each containing a known weight of artificial fruits (red, blue, black, or green) are introduced into the cage, while four equivalent trays are left outside the cage, to control for tray weight loss due to other factors (notably desiccation). The proposed univariate approach allows data from such designs to be analysed with adequate power and no major violations of statistical assumptions. Nevertheless, there is no single "best" approach for experiments of this type: the best analysis in each case will depend on the particular aims and nature of the experiments. © 2009 Elsevier Masson SAS. All rights reserved.

Hernandez-Gil J.,University of Valencia | Ferrer S.,University of Valencia | Castineiras A.,University of Santiago de Compostela | Lloret F.,University of Valencia
Inorganic Chemistry | Year: 2012

The title compound, characterized by means of an X-ray structure analysis, represents an easy example of a noncatena "1 + 2 + 1" tetranuclear copper(II) μ3-triazolate compound. [Cu4(atc) 2(dien)4(ClO4)2](ClO 4)2·2H2O (1), where H2atc = 5-amino-l,2,4-triazole-3-carboxylic acid and dien = diethylenetriamine = 1,4,7-triazaheptane, contains two copper atoms linked by a double diazinic bridge, each of which is further connected to a third and fourth copper atom (Cu′) through the triply bridging triazolato ring and the bidentate carboxylato group of the atc2- ligands. The copper-copper distances within the tetranuclear unit are Cu-Cu = 4.059 Å, Cu-Cu′ = 5.686 and 6.370 Å, and Cu′-Cu′ = 11.373 Å. The compound self-assembles into a tridimensional hydrogen-bonded network to generate a MOF. 1 exhibits antiferromagnetic behavior with g = 2.10(1), J = -34.1(2) cm -1 and j = -5.50(3) cm-1, where J is the coupling constant of the central Cu-Cu pair and j the coupling constant of the two Cu-Cu′ (Cucentral-Cupheripheral) pairs, as defined by H = -JS2S2a - j (S1S2 + S 2aS1a). Complex 1 has been tested as nuclease mimic. It shows good binding propensity to calf thymus DNA, with a binding constant value of 6.20 × 106 M-1 (Kapp) and ΔTm = 18.3 °C. Moreover, the compound displays efficient oxidative cleavage of pUC18 DNA, even at low concentration, in the presence of a mild reducing agent (ascorbate), with a rate constant for the conversion of supercoiled to nicked DNA (kobs) of ∼0.126 min-1. The good reactivity of 1 toward DNA is explained from the electrostatic interactions of the cationic species produced in solution. © 2012 American Chemical Society.

Bigazzi F.,Solvay Group | Cotroneb A.L.,Catholic University of Leuven | Tarrioc J.,University of Santiago de Compostela
Journal of High Energy Physics | Year: 2010

First and second order transport coefficients are calculated for the strongly coupled N = 4 SYMplasma coupled to massless fundamental matter in the Veneziano limit. The results, including among others the value of the bulk viscosity and some relaxation times, are presented at next-to-leading order in the flavor contribution. The bulk viscosity is found to saturate Buchel's bound. This result is also captured by an effective singlescalar five-dimensional holographic dual in the Chamblin-Reall class and it is suggested to hold, in the limit of small deformations, for generic plasmas with gravity duals, whenever the leading conformality breaking effects are driven by marginally (ir)relevant operators. This proposal is then extended to other relations for hydrodynamic coefficients, which are conjectured to be universal for every non-conformal plasma with a dual Chamblin-Realllike description. Our analysis extends to any strongly coupled gauge theory describing the low energy dynamics of N c ≫ 1 D3-branes at the tip of a generic Calabi-Yau cone. The fundamental fields are added by means of 1 ≪ N f ≪ N c homogeneously smeared D7-branes. © SISSA 2010.

Fioravanti D.,University of Bologna | Grinza P.,University of Santiago de Compostela | Rossi M.,National Institute of Nuclear Physics, Italy
Nuclear Physics B | Year: 2010

A method for determining the generalised scaling functions fn (g) arising in the high spin behaviour of long operator anomalous dimensions in the planar sl (2) sector of N = 4 SYM is proposed. The all-order strong coupling expansion is detailed for the prototypical third and fourth scaling functions (f3 (g), f4 (g), respectively) and - together with high-precision numerical computations - reveals itself as crucial for disentangling the emergence of the O (6) Non-Linear Sigma Model mass-gap from different SYM 'mass' functions. Remarkably, only the fourth one gains contribution from the non-BES reducible densities and also shows up, as first, NLSM interaction and specific model dependence. Finally, the computation of the n-th generalised function is sketched and might be easily finalised for checks versus the computations in the sigma model or the complete string theory. © 2009 Elsevier B.V. All rights reserved.

Chang C.L.,Chang Gung University | Cai J.J.,Stanford University | Cai J.J.,Texas A&M University | Lo C.,University College London | And 3 more authors.
Genome Research | Year: 2011

Diversities in human physiology have been partially shaped by adaptation to natural environments and changing cultures. Recent genomic analyses have revealed single nucleotide polymorphisms (SNPs) that are associated with adaptations in immune responses, obvious changes in human body forms, or adaptations to extreme climates in select human populations. Here, we report that the human GIP locus was differentially selected among human populations based on the analysis of a nonsynonymous SNP (rs2291725). Comparative and functional analyses showed that the human GIP gene encodes a cryptic glucose-dependent insulinotropic polypeptide (GIP) isoform (GIP55S or GIP55G) that encompasses the SNP and is resistant to serum degradation relative to the known mature GIP peptide. Importantly, we found that GIP55G, which is encoded by the derived allele, exhibits a higher bioactivity compared with GIP55S, which is derived from the ancestral allele. Haplotype structure analysis suggests that the derived allele at rs2291725 arose to dominance in East Asians ∼8100 yr ago due to positive selection. The combined results suggested that rs2291725 represents a functional mutation and may contribute to the population genetics observation. Given that GIP signaling plays a critical role in homeostasis regulation at both the enteroinsular and enteroadipocyte axes, our study highlights the importance of understanding adaptations in energy-balance regulation in the face of the emerging diabetes and obesity epidemics. © 2011 by Cold Spring Harbor Laboratory Press.

Requena J.R.,University of Santiago de Compostela | Wille H.,University of Alberta
Prion | Year: 2014

The structures of the infectious prion protein, PrPSc, and that of its proteolytically truncated variant, PrP 27-30, have evaded experimental determination due to their insolubility and propensity to aggregate. Molecular modeling has been used to fill this void and to predict their structures, but various modeling approaches have produced significantly different models. The disagreement between the different odelingsolutions indicates the limitations of this method. Over the years, in absence of a three-dimensional (3D) structure, a variety of experimental techniques have been used to gain insights into the structure of this biologically, medically, and agriculturally important isoform. Here, we present an overview of experimental results that were published in recent years, and which provided new insights into the molecular architecture of PrPSc and PrP 27-30. Furthermore, we evaluate all published models in light of these recent, experimental data, and come to the conclusion that none of the models can accommodate all of the experimental constraints. Moreover, this conclusion constitutes an open invitation for renewed efforts to model the structure of PrPSc.©2014 Landes Bioscience.

Larrinaga A.R.,University of Santiago de Compostela
Integrative Zoology | Year: 2011

One of the main hypotheses proposed to explain the evolution of fruit color deals with a preference of avian frugivores for specific colors, mainly black and red, which are the most common fruit colors in many of the studied habitats. I analyzed fruit color preferences by wild birds belonging to 2 species of the highly frugivorous genus Turdus (Eurasian Blackbird Turdus merula Linnaeus, 1758 and Redwing Turdus iliacus Linnaeus, 1758) by means of captivity experiments with artificial fruits. Despite important within-individual (i.e. temporal) and among-individual variability, consistent patterns of species-specific color preferences emerged. Eurasian Blackbirds tended to prefer red over blue, green and black, whereas Redwings seemed to prefer black over the rest. Green was systematically avoided by both species, suggesting that it might signal unripeness of fruits. Both preferred colors have been previously reported as the most common among fleshy-fruited plants. The high variability, both within and between individuals, in preferences suggests that they can be subject to changes through experience and learning and, therefore, are not likely to drive the evolution of fruit color. The main differences between both species could be related to the most common fruit color they fed upon during the last months before capture. © 2011 ISZS, Blackwell Publishing and IOZ/CAS.

Hoare B.,Humboldt University of Berlin | Hollowood T.J.,University of Swansea | Miramontes J.L.,University of Santiago de Compostela
Journal of High Energy Physics | Year: 2013

The world-sheet S-matrix of the string in AdS5×S 5 has been shown to admit a q-deformation that relates it to the S-matrix of a generalization of the sine-Gordon theory, which arises as the Pohlmeyer reduction of the superstring. Whilst this is a fascinating development the resulting S-matrix is not explicitly unitary. The problem has been known for a long time in the context of S-matrices related to quantum groups. A braiding relation often called "unitarity" actually only corresponds to quantum field theory unitarity when the S-matrix is Hermitian analytic and quantum group S-matrices manifestly violate this. On the other hand, overall consistency of the S-matrix under the bootstrap requires that the deformation parameter is a root of unity and consequently one is forced to perform the "vertex" to IRF, or SOS, transformation on the states to truncate the spectrum consistently. In the IRF formulation unitarity is now manifest and the string S-matrix and the S-matrix of the generalised sine-Gordon theory are recovered in two different limits. In the latter case, expanding the Yang-Baxter equation we find that the tree-level S-matrix of the Pohlmeyer-reduced string should satisfy a modified classical Yang-Baxter equation explaining the apparent anomaly in the perturbative computation. We show that the IRF form of the S-matrix meshes perfectly with the bootstrap equations.

Reboredo J.C.,University of Santiago de Compostela
Energy Economics | Year: 2011

This paper examines the dependence structure between crude oil benchmark prices using copulas. By considering several copula models with different conditional dependence structures and time-varying dependence parameters, we find evidence of significant symmetric upper and lower tail dependence between crude oil prices. These findings suggest that crude oil prices are linked with the same intensity during bull and bear markets, thus supporting the hypothesis that the oil market is 'one great pool'-in contrast with the hypothesis that states that the oil market is regionalized. Our findings on crude oil price co-movements also have implications for risk management, hedging strategies and asset pricing. © 2011 Elsevier B.V.

Calafat A.,European Institute of Studies on Prevention Irefrea | Garcia F.,University of Valencia | Juan M.,European Institute of Studies on Prevention Irefrea | Becona E.,University of Santiago de Compostela | Fernandez-Hermida J.R.,University of Oviedo
Drug and Alcohol Dependence | Year: 2014

Background: This study examines whether authoritative parenting style (characterized by warmth and strictness) is more protective against adolescent substances use than authoritarian (strictness but not warmth), indulgent (warmth but not strictness) and neglectful (neither warmth nor strictness) parenting styles. Emergent research in diverse cultural contexts (mainly Southern European and Latin American countries) questions the fact that authoritative would always be the optimum parenting style. Design: Multi-factorial MANOVAs. Participants: A sample of 7718 adolescents, 3774 males (48.9%), 11-19 year-olds (M= 14.63 year-olds, SD. = 1.9 years) from Sweden, United Kingdom, Spain, Portugal, Slovenia, and the Czech Republic. Measurements: Parenting style dimensions (warmth and strictness) and adolescent substance use (alcohol, tobacco, and illegal drugs); additionally another three adolescent outcomes were also measured (self-esteem, school performance and personal disturbances) all of them related in the literature with substance use. Findings: Both indulgent and authoritative parenting styles were associated with better outcomes than authoritarian and neglectful parenting in all the countries studied. Overall, our results support the idea that in Europe the indulgent parenting style performs as well as the authoritative one since adolescents' scores in the youth outcomes were equal (on substance use and personal disturbances) or even better (on self esteem and school performance) than for authoritative parenting style. Conclusions: Parenting styles relate to substance use and other outcomes in the same way in different countries explored. The so-called indulgent parenting style appears to be as good as the authoritative in protecting against substance abuse. © 2014 Elsevier Ireland Ltd.

Navarro-Vazquez A.,University of Santiago de Compostela
Magnetic Resonance in Chemistry | Year: 2012

We developed a new program, MSpin-RDC for the analysis of residual dipolar coupling data. This software, specially designed for small molecule analysis, can directly read many molecular-modeling and popular chemistry file formats and accept RDC values as a simple free-format table. Alignment tensor can then be computed by singular value decomposition, as well as predicted using inertia and gyration tensor-based methodologies. Trial structures are then ranked according to their Cornilescu's quality factor (Q) values. Analysis of multiconformational problems and fitting of RDC data to relative populations can be accomplished using the single-tensor approximation. Copyright © 2012 John Wiley & Sons, Ltd.

Alvarez-Castro J.M.,University of Santiago de Compostela
Current Genomics | Year: 2012

Models of genetic effects integrate the action of genes, regulatory regions and interactions among alleles across the genome. Such theoretical frameworks are critical for applied studies in at least two ways. First, discovering genetic networks with specific effects underlying traits in populations requires the development of models that implement those effects as parameters-adjusting the implementation of epistasis parameters in genetic models has for instance been a requirement for properly testing for epistasis in gene-mapping studies. Second, studying the properties and implications of models of genetic effects that involve complex genetic networks has proven to be valuable, whether those networks have been revealed for particular organisms or inferred to be of interest from theoretical works and simulations. Here I review the current state of development and recent applications of models of genetic effects. I focus on general models aiming to depict complex genotype-to-phenotype maps and on applications of them to networks of interacting loci. © 2012 Bentham Science Publishers.

Basilio N.,Singular | Martiin-Pastor M.,University of Santiago de Compostela | Garcia-Rio L.,Singular
Langmuir | Year: 2012

In this work, we have studied the interactions between the water-soluble p-sulfonatocalix[6]arene and cationic surfactants octyltrimethylammonium bromide below the cmc and dodecyltrimethylammonium bromide above the cmc, by saturation transfer difference (STD) NMR spectroscopy. From the STD build-up curves, we have obtained the T1 independent cross relaxation rates, and the results show that the interactions established between the cationic headgroup of the surfactant and the OMe group of the macrocycle play an important role in the stabilization of the complex, both below and above the cmc. © 2012 American Chemical Society.

Di Simplicio M.,University of Oxford | Doallo S.,University of Santiago de Compostela | Costoloni G.,University of Siena | Rohenkohl G.,University of Oxford | And 2 more authors.
Neuropsychopharmacology | Year: 2014

Anxiety and depression are associated with altered ocular exploration of facial stimuli, which could have a role in the misinterpretation of ambiguous emotional stimuli. However, it is unknown whether a similar pattern is seen in individuals at risk for psychopathology and whether this can be modified by pharmacological interventions used in these disorders. In Study 1, eye gaze movement during face discrimination was compared in volunteers with high vs low neuroticism scores on the Eysenck Personality Questionnaire. Facial stimuli either displayed a neutral, happy, or fearful expression. In Study 2, volunteers with high neuroticism were randomized in a double-blind design to receive the selective serotonin reuptake inhibitor citalopram (20 mg) or placebo for 7 days. On the last day of treatment, eye gaze movement during face presentation and the recognition of different emotional expressions was assessed. In Study 1, highly neurotic volunteers showed reduced eye gaze towards the eyes vs mouth region of the face compared with low neurotic volunteers. In Study 2, citalopram increased gaze maintenance over the face stimuli compared with placebo and enhanced recognition of positive vs negative facial expressions. Longer ocular exploration of happy faces correlated positively with recognition of positive emotions. Individuals at risk for psychopathology presented an avoidant pattern of ocular exploration of faces. Short-term SSRI administration reversed this bias before any mood or anxiety changes. This treatment effect may improve the capacity to scan social stimuli and contribute to the remediation of clinical symptoms related to interpersonal difficulties.Neuropsychopharmacology advance online publication, 13 August 2014; doi:10.1038/npp.2014.159.

Norman G.,University of Surrey | Pedley S.,University of Surrey | Takkouche B.,University of Santiago de Compostela | Takkouche B.,Research Center Biomedica En Red Of Epidemiologia lud Publica
The Lancet Infectious Diseases | Year: 2010

Background: Sanitation is inadequate in most cities in developing countries, with major effects on infectious disease burden: in this situation, is piped sewerage an appropriate solution, or should efforts focus on systems based on onsite solutions, such as latrines? We reviewed the effects of the presence of sewerage systems on diarrhoeal disease and related outcomes. We included only observational studies because so far there have been no randomised controlled trials. Methods: We identified relevant studies by use of a comprehensive strategy including searches of Medline and other databases from 1966 to February, 2010. In studies that compared sewerage with one other sanitation category, we used relative risk (RR) estimates for sewerage versus the other category. When a single study made two or more comparisons, we calculated a weighted average RR value, and used this value in our meta-analysis. We used the most adjusted RR estimate provided by the authors; if no adjusted estimate was available, we used the crude estimate. To obtain pooled-effect estimates, meta-analyses were done by use of an inverse variance method-ie, the study-specific adjusted log ORs for case-control and cross-sectional studies, and log RRs for cohort studies, were weighted by the inverse of their variance to compute a pooled RR with 95% CI. Findings: 25 studies investigated the association between sewerage and diarrhoea or related outcomes, including presence of intestinal nematodes. Pooled estimates show that sewerage systems typically reduce diarrhoea incidence by about 30% (RR 0·70, 95% CI 0·61-0·79), or perhaps as much as 60% when starting sanitation conditions are very poor. Studies with objective outcome measures showed even stronger pooled effect than studies that assessed diarrhoea incidence with interviews, while sensitivity analysis indicated that the effect remains even if we assume strong residual confounding. Interpretation: Sewerage interventions seem to reduce the incidence of diarrhoea and related outcomes. However, we urge cautious interpretation of these findings, because, in many contexts, sewerage might be less cost effective and sustainable than onsite alternatives. Funding: None. © 2010 Elsevier Ltd.

Izco J.,University of Santiago de Compostela
Plant Biosystems | Year: 2015

There are many proposals for the assessment of plant communities, based on different criteria, but very few proposals for categorization of the risk of extinction of plant communities (syntaxa). In this paper, concepts related to extent of occurence (EOO), area of occupancy (AOO), extinction and regeneration of plant communities are defined. Also, we propose and define several ranks of extinction risk based on quantitative criteria of the EOO, AOO and processes of decline. The proposals are global, for application to any type of cormophytic vegetation, without geographical restrictions. To check the adequacy of the proposed ranks and its thresholds, the method has been applied to the vegetation of the Iberian Peninsula based on the EOO (122 plant communities) and the AOO (2224 plant communities). © 2015 Società Botanica Italiana.

Arachnoid cysts are benign space-occupying lesions formed by an arachnoid membrane containing cerebrospinal fluid. Controversy continues regarding the optimal surgical management. There is ongoing debate regarding whether to fenestrate or to perform shunting of the cyst. We present a single-institution experience on surgical treatment of arachnoid cyst using cistoperitoneal shunt. This serie includes 49 children (31 males/18 females) with a diagnosis of intracranial arachnoid cyst and average age of 4-9 years (range 1-16). The predominant symptom was intracranial hypertension in 26 patients (53%). There were 12 complications in 10 patients. We conclude that arachnoid cyst are located predominantly in the temporal fossa. Cisto-peritoneal shunt is a good option in the younger children and have improved clinical symptoms.

Garcia C.,University of Santiago de Compostela
BMC Evolutionary Biology | Year: 2012

Background: Comparing the covariation patterns of populations or species is a basic step in the evolutionary analysis of quantitative traits. Here I propose a new, simple method to make this comparison in two population samples that is based on comparing the variance explained in each sample by the eigenvectors of its own covariance matrix with that explained by the covariance matrix eigenvectors of the other sample. The rationale of this procedure is that the matrix eigenvectors of two similar samples would explain similar amounts of variance in the two samples. I use computer simulation and morphological covariance matrices from the two morphs in a marine snail hybrid zone to show how the proposed procedure can be used to measure the contribution of the matrices orientation and shape to the overall differentiation. Results: I show how this procedure can detect even modest differences between matrices calculated with moderately sized samples, and how it can be used as the basis for more detailed analyses of the nature of these differences. Conclusions: The new procedure constitutes a useful resource for the comparison of covariance matrices. It could fill the gap between procedures resulting in a single, overall measure of differentiation, and analytical methods based on multiple model comparison not providing such a measure. © 2012 Garcia; licensee BioMed Central Ltd.

Paukkunen H.,University of Jyvaskyla | Paukkunen H.,Helsinki Institute of Physics | Salgado C.A.,University of Santiago de Compostela
Physical Review Letters | Year: 2013

The compatibility of neutrino-nucleus deep inelastic scattering data within the universal, factorizable nuclear parton distribution functions has been studied independently by several groups in the past few years. The conclusions are contradictory, ranging from a violation of the universality up to a good agreement, most of the controversy originating from the use of the neutrino-nucleus data from the NuTeV Collaboration. Here, we pay attention to non-negligible differences in the absolute normalization between different neutrino data sets. We find that such variations are large enough to prevent a tensionless fit to all data simultaneously and could therefore misleadingly point towards nonuniversal nuclear effects. We propose a concrete method to deal with the absolute normalization and show that an agreement between independent neutrino data sets is established. © 2013 American Physical Society.

Ferrin J.L.,University of Santiago de Compostela | Saavedra L.,Technical University of Madrid
Fuel Processing Technology | Year: 2013

The efficiency of a Power Plant is affected by the distribution of the pulverized coal within the furnace. The coal, which is pulverized in the mills, is transported and distributed by the primary gas through the mill-ducts to the interior of the furnace. This is done with a double function: dry and enter the coal by different levels for optimizing the combustion in the sense that a complete combustion occurs with homogeneous heat fluxes to the walls. The mill-duct systems of a real Power Plant are very complex and they are not yet well understood. In particular, experimental data concerning the mass flows of coal to the different levels are very difficult to measure. CFD modeling can help to determine them. An Eulerian/Lagrangian approach is used due to the low solid-gas volume ratio. © 2012 Elsevier B.V.

Fernandez E.F.,University of Jaen | Perez-Higueras P.,University of Jaen | Garcia Loureiro A.J.,University of Santiago de Compostela | Vidal P.G.,University of Jaen
Progress in Photovoltaics: Research and Applications | Year: 2013

For the behavior of concentrator photovoltaic systems technology under real conditions to be understood, different modules from different manufacturers were measured in a new research center in Jaén. The influence in the power and the efficiency of irradiation levels, air temperature, and the influence of air mass were under study for 6 months. Pmax shows a linear behavior with direct normal irradiance, and efficiency was constant to a first approximation for a wide range of irradiance levels. The effect of air temperature was negligible for the temperatures under study. At the same time, efficiency shows a maximum around AM1.5 and decreases aside this point. Copyright © 2012 John Wiley & Sons, Ltd.

Martinez-Nunez E.,University of Santiago de Compostela
Journal of Computational Chemistry | Year: 2015

A procedure to automatically find the transition states (TSs) of a molecular system (MS) is proposed. It has two components: high-energy chemical dynamics simulations (CDS), and an algorithm that analyzes the geometries along the trajectories to find reactive pathways. Two levels of electronic structure calculations are involved: a low level (LL) is used to integrate the trajectories and also to optimize the TSs, and a higher level (HL) is used to reoptimize the structures. The method has been tested in three MSs: formaldehyde, formic acid (FA), and vinyl cyanide (VC), using MOPAC2012 and Gaussian09 to run the LL and HL calculations, respectively. Both the efficacy and efficiency of the method are very good, with around 15 TS structures optimized every 10 trajectories, which gives a total of 7, 12, and 83 TSs for formaldehyde, FA, and VC, respectively. The use of CDS makes it a powerful tool to unveil possible nonstatistical behavior of the system under study. © 2014 Wiley Periodicals, Inc.

Lin H.,University of Santiago de Compostela
Journal of High Energy Physics | Year: 2012

We calculate non-extremal correlators of Schur polynomials and single trace operators. We analyse their dual descriptions from the approach of the variation of DBI and WZ actions of the giant gravitons. We show a regularization procedure under which the extremal correlators of Schur polynomials and single trace operators match exactly with string theory computation. Other aspects of the extremal and non-extremal correlators are also discussed. © 2012 SISSA, Trieste, Italy.

Reboredo J.C.,University of Santiago de Compostela
Energy Economics | Year: 2013

This paper examines the dependence structure between European Union allowances (EUAs) and crude oil markets during the second commitment period of the European Union Emissions Trading Scheme and the implications for portfolio management. Using different copula models, our findings suggest positive average dependence and extreme symmetric independence that is consistent with interdependence and no contagion effects between the EUA and crude oil markets. The implication of this result for EUA-oil portfolios points to the existence of diversification benefits, hedging effectiveness, and value-at-risk reductions. The EUA market is therefore an attractive market for investors in terms of diversifying market risk and reducing downside risk in crude oil markets. © 2012 Elsevier B.V.

Hoare B.,Imperial College London | Hollowood T.J.,University of Swansea | Miramontesc J.L.,University of Santiago de Compostela
Journal of High Energy Physics | Year: 2012

The investigation of the q deformation of the S-matrix for excitations on the string world sheet in AdS 5×S 5 is continued. We argue that due to the lack of Lorentz invariance the situation is more subtle than in a relativistic theory in that the nature of bound states depends on their momentum. At low enough momentum |p| < E the bound states transform in the anti-symmetric representation of the super-algebra symmetry and become the solitons of the Pohlmeyer reduced theory in the relativistic limit. At a critical momentum |p| = E they become marginally unstable, and at higher momenta the stable bound states are in the symmetric representation and become the familiar magnons in the string limit as q → 1. This subtlety fixes a problem involving the consistency of crossing symmetry with the relativistic limit found in earlier work. With mirror kinematics, obtained after a double Wick rotation, the bound state structure is simpler and there are no marginally unstable bound states. © SISSA 2012.

Serna J.,University of Santiago de Compostela
International Journal of Heat and Mass Transfer | Year: 2016

Steady two-dimensional nanofluids boundary layers are studied with focus on heat and mass transfer properties. The study is conducted by numerical analysis of the nonlinear boundary layer equations in a self-similar form for the case of constant wall temperature. The density, specific heat, viscosity, conductivity, and thermal diffusion dependence on the solid-phase volumetric fraction are considered, as well as the brownian diffusion dependence on temperature. Under the assumption of dilute mixtures, the zeroth order solution is calculated as an approach to the particles distribution in the boundary layer and it is compared with the results obtained from the full equations solutions. The effects of the Schmidt number, the wall temperature, and the particle bulk volumetric fraction on the Nusselt number, the Sherwood number, and the skin-friction coefficient are elucidated and compared to the values obtained for the pure fluid and for uniform mixtures. An increase in the heat transfer performances with respect to the case of the base fluid is found for most of the cases. © 2015 Elsevier Ltd. All rights reserved.

Jokela N.,University of Santiago de Compostela | Jokela N.,Instituto Galego Of Fisica Of Altas Enerxias Igfae | Lifschytz G.,Haifa University | Lippert M.,University of Crete
Journal of High Energy Physics | Year: 2012

We explore the magnetic properties of the Fermi-like liquid represented by the D3-D7' system. The system exhibits interesting magnetic properties such as ferromagnetism and an anomalous Hall effect, which are due to the Chern-Simons term in the effective gravitational action. We investigate the spectrum of quasi-normal modes in the presence of a magnetic field and show that the magnetic field mitigates the instability towards a striped phase. In addition, we find a critical magnetic field above which the zero sound mode becomes massive. © SISSA 2012.

Baker-Austin C.,CEFAS - Center for Environment, Fisheries and Aquaculture Science | Stockley L.,CEFAS - Center for Environment, Fisheries and Aquaculture Science | Rangdale R.,CEFAS - Center for Environment, Fisheries and Aquaculture Science | Martinez-Urtaza J.,University of Santiago de Compostela
Environmental Microbiology Reports | Year: 2010

Vibrio vulnificus and Vibrio parahaemolyticus are ubiquitous Gram-negative bacterial pathogens found naturally in marine and estuarine waters, and are a leading cause of seafood-associated bacterial illness. These pathogens are commonly reported in the USA and in many Asian countries, including China, Japan and Taiwan; however, there is growing concern that V. vulnificus and V. parahaemolyticus may represent an important and increasing clinical problem in Europe. Several factors underlie the need for a greater understanding of these non-cholera vibrios within a European context. First, there is a growing body of evidence to suggest that V. vulnificus and V. parahaemolyticus infections are increasing, and tend to follow regional climatic trends, with outbreaks typically following episodes of unusually warm weather. Such findings are especially alarming given current predictions regarding warming of marine waters as a result of global climatic change. Second, a myriad of epidemiological factors may greatly increase the incidence as well as clinical burden of these pathogens-including increasing global consumption and trade of seafood produce coupled to an increase in the number of susceptible individuals consuming seafood produce. Finally, there is currently a lack of detailed surveillance information regarding non-cholerae Vibrio infections in Europe, as these pathogens are not notifiable in many countries, which probably masks the true clinical burden of many human infections. This review will present a pertinent overview of both the environmental occurrence and clinical impact of V. vulnificus and V. parahaemolyticus in Europe. © 2010 Crown.

Losada D.E.,University of Santiago de Compostela
Information Retrieval | Year: 2010

The retrieval of sentences that are relevant to a given information need is a challenging passage retrieval task. In this context, the well-known vocabulary mismatch problem arises severely because of the fine granularity of the task. Short queries, which are usually the rule rather than the exception, aggravate the problem. Consequently, effective sentence retrieval methods tend to apply some form of query expansion, usually based on pseudo-relevance feedback. Nevertheless, there are no extensive studies comparing different statistical expansion strategies for sentence retrieval. In this work we study thoroughly the effect of distinct statistical expansion methods on sentence retrieval. We start from a set of retrieved documents in which relevant sentences have to be found. In our experiments different term selection strategies are evaluated and we provide empirical evidence to show that expansion before sentence retrieval yields competitive performance. This is particularly novel because expansion for sentence retrieval is often done after sentence retrieval (i.e. expansion terms are mined from a ranked set of sentences) and there are no comparative results available between both types of expansion. Furthermore, this comparison is particularly valuable because there are important implications in time efficiency. We also carefully analyze expansion on weak and strong queries and demonstrate clearly that expanding queries before sentence retrieval is not only more convenient for efficiency purposes, but also more effective when handling poor queries. © 2010 Springer Science+Business Media, LLC.

Gracia A.,Research Center cnologia Agroalimentaria Of Aragon Cita | Loureiro M.L.,University of Santiago de Compostela | Nayga R.M.,University of Arkansas
American Journal of Agricultural Economics | Year: 2011

Due to the importance of comparability and external validity of results, nonhypothetical experimental methods are increasingly used to elicit consumers' willingness to pay for various goods. Two of the increasingly popular preference elicitation methods are the nonhypothetical choice experiments and experimental auctions. We conduct experiments to compare willingness to pay estimates elicited from both methods. Our results generally suggest that valuations elicited from experimental auctions can differ from those obtained from nonhypothetical choice experiments. © TheAuthor (2011). Published by Oxford University Press on behalf of the Agricultural and Applied Economics Association. All rights reserved.

Lopez F.,Institute Quimica Organica General | Mascarenas J.L.,University of Santiago de Compostela
Chemistry - A European Journal | Year: 2011

Allenes are very versatile synthetic units that are used in many types of catalytic cycloaddition reactions. Most examples reported so far involve their use as 2C-atom components, whereas their participations as 3C-atom components have been much less frequent. In this concept article, we present an overview of this latter strategy, emphasizing on those more recent contributions involving the use of Pt II and Au I catalysts, which have uncovered new opportunities in this area. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bujan E.,University of Santiago de Compostela
Quaternary International | Year: 2013

Plants accumulate opaline silica in the form of phytoliths. Species and availability of Si are the main factors that determine the phytolith content in plants. Therefore, several Ericaceae species were tested in different soils. Erica andevalensis is restricted to grow in acid- and metal-enriched soils in the Iberian Pyritic Belt, and therefore it is particularly suitable to study the effects of metals on the phytolith composition. Ericaceae that originate from soils in mining areas were compared with those from unpolluted areas. Species from mining areas included E. andevalensis (Riotinto mines, Andalucía, SW Spain), Erica australis and Calluna vulgaris (Touro mine Galicia, NW Spain). For the unpolluted areas, C. vulgaris was collected on peat (Sapric Histosol), quartzite (Albic Podsol) and serpentinite (Mollic Gleysol) soils. The abundance and elemental composition (Ca, Mg, Al, Fe, Mn, Cu, Zn, Cr, Ni, Pb and As) of phytoliths in leaves were analyzed. Elemental quantification by means of Energy-dispersive Miniprobe Multielement Analyzer (EMMA-XRF) is an innovative method for elemental analysis of phytoliths. Both the highest leaf phytolith production and elemental concentration were found in species from mine soils, with the highest phytolith contents for C. vulgaris and highest concentration of elements (Ca, Fe, Mn, Cu, Zn, Pb and As) for E. andevalensis. The highest Cr and Ni concentration in phytoliths was found on serpentinite soils. The lowest values of phytoliths and metal concentrations were found in heathers from quartzite and peaty soils.The abundance of phytoliths agreed with the availability of Si in the studied soils and its elemental composition reflected the geochemical conditions. The results presented here suggest that phytoliths act as alleviates of metal stress in heathers. © 2012 Elsevier Ltd and INQUA.

Moeder M.,Helmholtz Center for Environmental Research | Schrader S.,Helmholtz Center for Environmental Research | Winkler U.,Helmholtz Center for Environmental Research | Rodil R.,University of Santiago de Compostela
Journal of Chromatography A | Year: 2010

An at-line analysis protocol is presented that allows the determination of four UV filters, two polycyclic musk compounds and caffeine in water at concentration level of ng L-1. The fully automated method includes analytes enrichment by Microextraction by packed sorbent (MEPS) coupled directly to large volume injection-gas chromatography-mass spectrometry. Two common SPE phases, C8 and C18, were examined for their suitability to extract the target substances by MEPS. The analytes were extracted from small sample volumes of 800μL with recoveries ranging from 46 to 114% for the C8-sorbent and 65-109% for the C18-sorbent. Limits of detection between 34 and 96 ng -1 enable the determination of the analytes at common environmental concentration levels. Both sorbents showed linear calibration curves for most of the analytes up to a concentration level of 20 ngm-1. Carryover was minimized by washing the sorbents 10 times with 100μL methanol. After this thorough cleaning, the MEPS are re-used and up to 70 analyses can be performed with the same sorbent. The fully automated microextraction GC-MS protocol was evaluated for the influence of matrix substances typical for wastewater. Dilution of samples prior to MEPS is recommended when the polar caffeine is present at high concentration. Real water samples were analyzed by the MEPS-GC-MS method and compared to standard SPE. © 2010 Elsevier B.V.

Ortiz-Barahona A.,Autonomous University of Madrid | Villar D.,Autonomous University of Madrid | Pescador N.,Autonomous University of Madrid | Amigo J.,University of Santiago de Compostela | del Peso L.,Autonomous University of Madrid
Nucleic Acids Research | Year: 2010

The transcriptional response driven by Hypoxiainducible factor (HIF) is central to the adaptation to oxygen restriction. Hence, the complete identification of HIF targets is essential for understanding the cellular responses to hypoxia. Herein we describe a computational strategy based on the combination of phylogenetic footprinting and transcription profiling meta-analysis for the identification of HIF-target genes. Comparison of the resulting candidates with published HIF1a genome-wide chromatin immunoprecipitation indicates a high sensitivity (78%) and specificity (97.8%). To validate our strategy, we performed HIF1a chromatin immunoprecipitation on a set of putative targets. Our results confirm the robustness of the computational strategy in predicting HIFbinding sites and reveal several novel HIF targets, including RE1-silencing transcription factor co-repressor (RCOR2). In addition, mapping of described polymorphisms to the predicted HIF-binding sites identified several singlenucleotide polymorphisms (SNPs) that could alter HIF binding. As a proof of principle, we demonstrate that SNP rs17004038, mapping to a functional hypoxia response element in the macrophage migration inhibitory factor (MIF) locus, prevents induction of this gene by hypoxia. Altogether, ourresults show that the proposed strategy is a powerful tool for the identification of HIF direct targets that expands our knowledge of the cellular adaptation to hypoxia and provides cues on the inter-individual variation in this response. © The Author(s) 2010. Published by Oxford University Press.

Fagundez J.,IE University | Izco J.,University of Santiago de Compostela
Turkish Journal of Botany | Year: 2011

The species of the "Pentapera group" are distinguished from the rest of the European and Mediterranean Erica L. species by having 5 corolla lobes and sepals instead of 4, and 10 stamens instead of 8. The genus Pentapera Klotzsch was proposed for these taxa but recent studies regards it as part of Erica. Two species are recognised: Erica sicula Guss. and E. bocquetii (Peşmen) P.F.Stevens, and 3 subspecies have been described within E. sicula. This taxonomic treatment is still under discussion and relationships with other species have been poorly discussed. Seed morphology of the 2 species and the 3 subspecies was studied by means of scanning electron microscope techniques. Characters concerning size and shape of seeds, and primary and secondary ornamentation were observed and measured. Anatomy of the seed coat was analysed in 2 populations of E. sicula subsp. libanotica (C.Barbey) P.F.Stevens using a light microscope, and seed coat thickness and cell junctions were measured. Seeds range from 0.45 to 0.8 mm; shape is ellipsoid, oblong, or obovoid with a lateral wing; primary ornamentation is striate while secondary ornamentation shows smooth outer anticlinal walls and indented or smooth outer periclinal walls. Clear differences were found for the studied taxa. The seeds of E. bocquetii have the lowest values for size and lack an indented surface; this is shared with E. sicula subsp. libanotica. E. sicula subsp. sicula has an indented surface and E. sicula subsp. cyrenaica Brullo & Furnari has smaller, rounder seeds. Compared to the rest of the northern Erica species, seed coat sections reveal similarities with E. arborea L. and E. australis L, and seed morphology relate this group with E. ciliaris L. but most of all with E. arborea. © TÜBİTAK.

A Stx2a-producing Escherichia coli (STEC) strain belonging to serotype O104:H4, with virulence features common to the enteroaggregative E. coli pathotype, was reported as the cause of the recent 2011 outbreak in Germany. In addition, the German outbreak strain was found to possess several virulence factors of extra-intestinal pathogenic E. coli and to have acquired resistance to numerous antibiotics, including third-generation cephalosporins, owing to several plasmid-borne genes encoding TEM-1 and CTX-M-15 β-lactamases. There are only a few reports of serotype O104:H4, which is very rare in humans, and has never been detected in animals or food. Once the serotype of the German outbreak strain became known, specific molecular methods were developed for its detection based on conventional and real-time PCR. Data from Galicia suggest that, per year in Spain, STEC O157:H7 is responsible for more than 500 cases of infection, and non-O157 for more than 2,000. A microbiological diagnosis for O104:H4, O157:H7 and other STEC serotypes is required in Spanish hospitals. © 2011 Elsevier España, S.L. All rights reserved.

Santana L.,University of Santiago de Compostela
Current topics in medicinal chemistry | Year: 2015

The use of the nanotechnology in the development of new drugs has had in the last years a very widespread presence in the pharmaceutical industry. Diverse diseases that are treated by means of conventional administration systems as capsules, covered tablets or injectable not always have the therapeutic effect expected due to its bioavailability, solubility in aqueous medium and the stability of the excipients that they accompany to the drug. It is for this reason that the formation of nanoparticles either from organic sources as natural polymers like chitosan or synthetic like poly-ε-caprolactone (PCL) affording the inclusion of diverse liposoluble active compounds, they have given excellent results in the incipient treatment of behavior disorders that are necessary drugs that should remain close of active sites at the time. Thus, this review shows the formation of nanoparticles for a direct application of the psychiatric medication, may be considered as a new pharmacological tool by its low cytotoxicity and high efficiency.

Hollowood T.J.,University of Swansea | Miramontes J.L.,University of Santiago de Compostela | Schmidtt D.M.,University of Swansea | Schmidtt D.M.,Sao Paulo State University
Journal of High Energy Physics | Year: 2014

A general class of deformations of integrable sigma-models with symmetric space F/G target-spaces are found. These deformations involve defining the non-abelian T dual of the sigma-model and then replacing the coupling of the Lagrange multiplier imposing flatness with a gauged F/F WZW model. The original sigma-model is obtained in the limit of large level. The resulting deformed theories are shown to preserve both integrability and the equations-of-motion, but involve a deformation of the symplectic structure. It is shown that this deformed symplectic structure involves a linear combination of the original Poisson bracket and a generalization of the Faddeev-Reshetikhin Poisson bracket which we show can be re-expressed as two decoupled F current algebras. It is then shown that the deformation can be incorporated into the classical model of strings on (formula presented) via a generalization of the Pohlmeyer reduction. In this case, in the limit of large sigma-model coupling it is shown that the theory becomes the relativistic symmetric space sine-Gordon theory. These results point to the existence of a deformation of this kind for the full Green-Schwarz superstring on AdS5 × S5. © 2014, The Author(s).

Moreira J.,University of Santiago de Compostela | Parapar J.,University of La Coruna
Polar Biology | Year: 2011

The examination of polychaete collections obtained during the Spanish Bentart 2006 expedition to the Bellingshausen Sea (Antarctica) revealed the presence of several sphaerodorid species. In this work, species belonging to the genera Sphaerodorum Örsted, 1843, Ephesiella Chamberlin, 1919, Clavodorum Hartman and Fauchald, 1971 and Sphaerephesia Fauchald, 1972 are reported including two new species belonging to Sphaerodorum and Sphaerephesia, respectively. A specimen identified as Ephesiella sp. might also represent a new species but, due to its poor state of preservation, a formal description is not possible yet. Furthermore, Sphaerodoropsis polypapillata Hartmann-Schröder and Rosenfeldt, 1988 is transferred to the genus Clavodorum Hartman and Fauchald, 1971 after examination of the type series and specimens obtained from the Bellingshausen Sea. © 2010 Springer-Verlag.

Villasante S.,University of Santiago de Compostela | Sumaila U.R.,University of British Columbia
Marine Policy | Year: 2010

By comparing the real reductions in fishing capacity of the European Union (EU) and the effects of technological efficiency, this paper presents the first comprehensive analysis since the creation of the Common Fisheries Policy (CFP). Using a standard methodology and a conservative value of ±4.4% for annual technological progress, the results obtained for tonnage indicated that the EU-13 fleet's fishing capacity was reduced by >4% for only three years (1991, 2004, and 2006) in the 1987-2006 period. This result shows that technological efficiency always grew faster than the real reduction of fishing capacity. Moreover, the reduction of the fishing power of the EU-13 fleet exceeded 4% annually only in 1991 (5.2%), 2004 (6.6%), and 2006 (6.5%). These results demonstrate a high level of incoherence and inefficiency of the CFP in terms of reducing fishing capacity over time. The results presented here highlight the fact that the overcapacity problem is the key issue that should be addressed by the next CFP-reform. © 2009 Elsevier Ltd. All rights reserved.

Cea L.,University of La Coruna | Vazquez-Cendon M.E.,University of Santiago de Compostela
Journal of Computational Physics | Year: 2012

The finite volume discretisation of the shallow water equations has been the subject of many previous studies, most of which deal with a well-balanced conservative discretisation of the convective flux and bathymetry. However, the bed friction discretisation has not been so profusely analysed in previous works, while it may play a leading role in certain applications of shallow water models. In this paper we analyse the numerical discretisation of the bed friction term in the two-dimensional shallow water equations, and we propose a new unstructured upwind finite volume discretisation for this term. The new discretisation proposed improves the accuracy of the model in problems in which the bed friction is a relevant force in the momentum equation, and it guarantees a perfect balance between gravity and bed friction under uniform flow conditions. The relation between the numerical scheme used to solve the hydrodynamic equations and the scheme used to solve a scalar transport model linked to the shallow water equations, is also analysed in the paper. It is shown that the scheme used in the scalar transport model must take into consideration the scheme used to solve the hydrodynamic equations. The most important implication is that a well-balanced and conservative scheme for the scalar transport equation cannot be formulated just from the water depth and velocity fields, but has to consider also the way in which the hydrodynamic equations have been solved. © 2012 Elsevier Inc.

Astariz S.,University of Santiago de Compostela | Iglesias G.,University of Plymouth
Renewable and Sustainable Energy Reviews | Year: 2015

Wave energy is arguably one of the most promising renewables. Less developed at present than other renewables, the existing models to estimate the costs of a wave energy project are often oversimplified, and the resulting scatter in the economic assessments weighs on the confidence of potential investors and constitutes therefore an impediment to the development of wave energy. Indeed, understanding the costs of wave energy is one of the main fields of research in marine renewable energy. In this context, the main objective of this paper is to review all the factors that must be considered in an economic analysis of wave energy, including a number of elements that are usually overlooked. In the process we characterise the direct and indirect costs of a wave farm - preliminary costs, construction, operation and maintenance and decommissioning cost - as well as its prospective incomes. For each of them a reference value is presented, together with a generic formula for its calculation. Moreover, the levelised cost, i.e., the production cost of an energy unit (1 kW h), is compared between various energy sources, and on these grounds conclusions on the profitability and competitiveness of wave energy are drawn. In sum, this work reviews the state of the art and sets the basis for a thorough economic analysis of wave energy. © 2015 Elsevier Ltd. All rights reserved.

Velando A.,University of Vigo | Munilla I.,University of Santiago de Compostela
Biological Conservation | Year: 2011

The provision of recreational opportunities is one of the important human goals of marine protected areas. However, as levels of recreational use increase, human disturbance is likely to cause significant detrimental effects upon wildlife. Here we evaluate the best managing options to mitigate the impact of sea-based tourism on the foraging activity of an endangered population of European shags, Phalacrocorax aristotelis, in a coastal marine protected area (Cíes islands, north-western Iberia). Boat disturbance elicited a characteristic avoidance behavior that resulted in a substantial reduction in foraging activity as levels of boat use increased. Moreover, boats excluded shags from the best feeding areas, resulting in higher densities of foragers in areas of little boat traffic. We used a behavioral model to explore the effects of managing strategies aimed at reducing the impact of boats on the foraging activity of shags. Our model suggested that in low boat disturbance scenarios limiting the number of boats using the reserve would be a better management option than habitat protection (i.e. the establishment of set-aside areas free of boat traffic). On the contrary, when boat disturbance levels are high the protection of habitat is recommendable, even if spatial variation in habitat quality is unknown or poorly assessed. Our study stresses the point that management strategies to minimize disturbance to foraging seabirds may depend on the spatial overlap between sea-based recreational activities and foraging seabirds and the spatial variation in marine habitat quality for seabirds. © 2011 Elsevier Ltd.

Schellekens J.,University of Santiago de Compostela | Buurman P.,Wageningen University | Kuyper T.W.,Wageningen University
Soil Biology and Biochemistry | Year: 2012

We identified the effects of vegetation changes, and aerobic and anaerobic decay on the lignin composition in the Penido Vello peat record (Galicia, Spain). The ombrotrophic part of this peat record was dominated by graminoids and has significant contributions of ericoids at some depths. The organic matter (OM) of different peat fractions (bulk, NaOH-extractable fraction, and non-extractable residues) of 15 samples from the upper meter was analysed with pyrolysis-gas chromatography/mass spectrometry (pyrolysis-GC/MS). In addition, the dominant plant species were analysed, including Carex durieui, Agrostis curtisii, Molinia caerulea, Deschampsia flexuosa, Festuca rubra, Eriophorum angustifolium, Erica mackaiana and Calluna vulgaris, and their lignin composition compared to that of the peat OM. The high abundance of guaiacol and 4-formylguaiacol in fresh plant tissue compared to peat OM suggests that in addition to p-coumaric and ferulic acid (which are abundant in graminoids), other non-lignin phenolic monomers are contributed by graminoid species. For the non-lignin phenolics, graminoids differed from ericoids in the high abundance of ferulic acid (4-vinylguaiacol), while p-coumaric acid (4-vinylphenol) showed high and similar abundances in ericoids and graminoids. This result suggests that ratios between p-hydroxyphenyl (or p-coumaric acid) and other lignin moieties in (pyrolysates of) peat cannot be used as source indicator. Comparison of plant and peat fractions using factor analysis allowed a distinction between the effects of source (plant identity) and decay on the lignin composition of the Penido Vello peat, and different stages of decomposition were identified. Preferential decay of guaiacyl over syringyl moieties was found for the first stage of decay. This preferential decay is probably related to the large abundance of guaiacyl moieties in easily degradable non-lignin phenolics. Preferential decay of syringyl moieties occurred during subsequent aerobic decay. © 2012 Elsevier Ltd.

Gurau G.,University of Alabama | Rodriguez H.,University of Santiago de Compostela | Kelley S.P.,University of Alabama | Janiczek P.,Proionic GmbH Parkring 18 | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2011

Real chemistry: Spectroscopic and crystallographic analyses confirm the chemical reaction of CO 2 with carbene present in 1,3- dialkylimidazolium acetate ionic liquids and the supporting role of the acetate ion. When CO 2 was bubbled through [C 2mim][OAc], formation of the corresponding imidazolium carboxylate, [C 2mim +-COO -], could be observed. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fernandez J.R.,University of Vigo | Muniz M.C.,University of Santiago de Compostela
Journal of Mathematical Chemistry | Year: 2011

This paper focuses on the surfactant behavior at air-water interface, taking into account the diffusion-controlled model together with the Henry isotherm to model the relation between the surface and the subsurface concentrations. The existence and uniqueness of a weak solution is stated. Fully discrete approximations are obtained by using a finite element method and the backward Euler scheme. Error estimates are then proved from which, under adequate additional regularity conditions, the linear convergence of the algorithm is derived. Finally, some numerical simulations are presented in order to demonstrate the accuracy of the algorithm and the behavior of the solution. © 2011 Springer Science+Business Media, LLC.

Ferreiro E.G.,University of Santiago de Compostela
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

We present our results on charmonium production at the Large Hadron Collider energies within the comover interaction model. The formalism includes both comover dissociation of J/ψ's and possible secondary J/ψ production through recombination. The estimation of this effect is made without involving free parameters. The comover interaction model also incorporates an analytic treatment of initial-state nuclear shadowing. With these tools, the model successfully describes the centrality, transverse momentum and rapidity dependence of the experimental data from PbPb collisions at the LHC energy of s=2.76 TeV. We present predictions for PbPb collisions at s=5.5 TeV. © 2014 Elsevier B.V.

Fernandez J.R.,University of Vigo | Garcia-Aznar J.M.,Aragon Institute of Engineering Research | Martinez R.,University of Santiago de Compostela
Journal of Theoretical Biology | Year: 2012

We have developed a mathematical approach for modelling the piezoelectric behaviour of bone tissue in order to evaluate the electrical surface charges in bone under different mechanical conditions. This model is able to explain how bones change their curvature, where osteoblasts or osteoclasts could detect in the periosteal/endosteal surfaces the different electrical charges promoting bone formation or resorption. This mechanism also allows to understand the BMU progression in function of the electro-mechanical bone behaviour. © 2011 Elsevier Ltd.

Dominguez-Munoz J.E.,University of Santiago de Compostela
Clinical Gastroenterology and Hepatology | Year: 2011

Exocrine pancreatic insufficiency with steatorrhea is a major consequence of chronic pancreatitis. Recognition of this entity is highly relevant to avoid malnutrition-related morbidity and mortality. Nutritional counseling and oral pancreatic enzyme replacement are the basis for the therapy for exocrine pancreatic insufficiency. Aim of enzyme therapy is not only to avoid symptoms but also to normalize digestion. With this aim, oral administration of pancreatic enzymes in the form of enteric-coated minimicrospheres is the therapy of choice. This enzyme preparation avoids acid-mediated lipase inactivation and ensures gastric emptying of enzymes in parallel with nutrients. Despite that, factors like an acidic intestinal pH and bacterial overgrowth may prevent normalization of fat digestion even in compliant patients. The present article reviews the current evidence on therapy of exocrine pancreatic insufficiency in chronic pancreatitis patients, with special attention to different potential endpoints to select the optimal enzyme dose for individual patients. © 2011 AGA Institute.

Beuf G.,University of Santiago de Compostela
Nuclear Physics A | Year: 2014

An improved version of the Balitsky-Kovchegov equation is presented, with a consistent treatment of kinematics. That improvement allows to resum the most severe of the large higher order corrections which plague the conventional versions of high-energy evolution equations, with approximate kinematics. This result represents a further step towards having high-energy QCD scattering processes under control beyond strict Leading Logarithmic accuracy and with gluon saturation effects. © 2014 Elsevier B.V.

Perez-Zafrilla B.,Complejo Hospitalario Universitario Of Albacete | Carmona L.,Research Unit | Gomez-Reino J.J.,University of Santiago de Compostela
Current Pharmaceutical Biotechnology | Year: 2012

TNF has a critical role in inflammation and immunity, and therapeutic inhibition of TNF with antagonist could potentially lead to immune suppression. Data gathered from clinical trials and clinical observation show a minor but significant increased risk of infections in patients suffering from rheumatic diseases treated with monoclonal TNF antibodies and soluble TNF receptors. This increase risk applies to patients but also to the underlying disease. Pathogens causing these infections include intracellular bacteria, and to some extend opportunistic microorganisms as mycobacteria and fungi. Preventive strategies and patient selection have an important impact on the risk of these infections. © 2012 Bentham Science Publishers.

Veigas M.,University of Santiago de Compostela | Iglesias G.,University of Plymouth
Energy Conversion and Management | Year: 2014

The island of Fuerteventura (Spain), on its way towards energy self-sufficiency, is investing in renewable sources to produce green energy. In this manner the island, a UNESCO Biosphere Reserve, would be able to decrease its carbon footprint. Considering these goals, the main objective of this work is to investigate the output energy from renewable energy sources, and in particular, wave and offshore wind by means of the installation of a hybrid offshore wave-wind farm off the western coast of the island, where the resource is substantial. The farm, consisting of offshore wind turbines and co-located wave energy converters (WECs), would realise the synergies between wave and offshore wind energy. As a second objective, the impact caused on the nearshore climate in terms of deficit of wave height is investigated by means of the implementation of the SWAN model. It is found that, on the one hand, the impact generated is not very noticeable, and on the other hand, the produced energy constitutes an excellent approach to satisfying the energy needs of the island. © 2014 Elsevier Ltd. All rights reserved.

Ramallo A.V.,University of Santiago de Compostela
Springer Proceedings in Physics | Year: 2015

This is a pedagogical introduction to the AdS/CFT correspondence. Starting with the conceptual basis of the holographic dualities, the subject is developed emphasizing some concrete topics, which are discussed in detail. A very brief introduction to string theory is provided, containing theminimal ingredients to understand the origin of the AdS/CFT duality. Other topics covered are the holographic calculation of correlation functions, quark–antiquark potentials and transport coefficients. © Springer International Publishing Switzerland 2015.

Miguez-Macho G.,University of Santiago de Compostela | Fan Y.,Rutgers University
Journal of Geophysical Research: Atmospheres | Year: 2012

Observational studies across the Amazon report a common occurrence of shallow water table in lowland valleys and groundwater-surface water exchange from small headwater catchments to large floodplains. In this study, we assess groundwater's role in the Amazon surface water dynamics using a continental-scale coupled groundwater-surface water model (LEAF-Hydro-Flood) forced by ERA-Interim reanalysis, at 2km and 4min resolution over 11years (2000-2010). The simulation is validated with observed streamflow, water table depth and flooding extent. A parallel simulation without groundwater is conducted to isolate its effect. Our findings support the following hypotheses. First, in the headwater catchments, groundwater dominates streamflow; the observed variations in its dominance across the Amazon can be explained by the varying water table depth. Second, over large floodplains, there are two-way exchanges between floodwater and groundwater as infiltration in the wet season and seepage in the dry season, and the direction and magnitude are controlled by the water table depth. Third, the Amazon harbors large areas of wetlands that are rarely under floodwater and difficult to observe by remote sensing, but are maintained by a persistently shallow water table. Fourth, due to its delayed and muted response to rainfall, groundwater seepage persists in the dry season, buffering surface waters through seasonal droughts. Our simulations shed new lights on the spatial-temporal structures of the hidden subsurface hydrologic pathways across the Amazon and suggest possible mechanisms whereby groundwater actively participates in the Amazon water-carbon cycle such as CO2 outgassing from groundwater seeps and CH4 emission from groundwater-supported wetlands. © 2012. American Geophysical Union. All Rights Reserved.

Lorenzo J.M.,Centro Tecnologico Of La Carne Of Galicia | Sineiro J.,University of Santiago de Compostela | Amado I.R.,CSIC - Institute of Marine Research | Franco D.,Centro Tecnologico Of La Carne Of Galicia
Meat Science | Year: 2014

In this study four natural extracts from tea (TEA), grape (GRA), chestnut (CHE) and seaweed (SEA) with potential antioxidant activity were evaluated in pork patties. During 20. days of storage in modified atmosphere packs at 2. °C, pH, colour, lipid oxidation and microbial spoilage parameters of raw minced porcine patties were examined and compared with a synthetic antioxidant (BHT) and control (CON) batch. Due to their higher polyphenol content, GRA and TEA extracts were the most effective antioxidants against lipid oxidation, also limiting colour deterioration. In addition, both natural extracts led to a decrease of total viable counts (TVC), lactic acid bacteria (LAB), Pseudomonas and psychotropic aerobic bacteria compared to the control. Among the four natural compounds tested, tea and grape extracts showed the most potential as alternatives to commercial antioxidants, for increasing the quality and extending the shelf-life of porcine patties. © 2013 Elsevier Ltd.

Flores J.R.,University of Santiago de Compostela
Optometry and Vision Science | Year: 2010

Purpose.: To obtain analytical formulas for calculating the ocular rotation and the prismatic effect with a general lens, centered or decentered, with particular reference to thick spherotoric spectacle lenses. Methods.: Linear theory is used, using the symplectic properties of optical matrices, to derive the desired formulas. Results.: By applying the general formulas to particular cases, the corresponding formulas are obtained, sometimes recovering formulas already known. Two examples serve to illustrate the use of the formulas obtained and to compare the results they provide with the ones obtained by exact ray tracing. Conclusions.: The linear formulas derived allow to find, in a rather easy way, quite accurate values of the ocular rotation and the prismatic effect in the paraxial region. Copyright © 2010 American Academy of Optometry.

Iglesias G.,University of Plymouth | Carballo R.,University of Santiago de Compostela
Renewable Energy | Year: 2014

The objective of this work is to investigate how the impact of a wave farm on the nearshore wave conditions depends on its location and, more specifically, its distance to the coast. For this purpose eight case studies in an area with a very substantial wave resource are considered; they encompass three values of the farm-to-coast distance (2km, 4km and 6km) plus a baseline situation (with no farm), in combination with two wave conditions representative of winter and summer scenarios. A coastal wave model is implemented on a high-resolution nested grid. The interaction between the individual Wave Energy Converters (WECs) of the array and the waves is simulated by the model on the basis of experimental data, i.e., the wave transmission coefficients are obtained from laboratory tests. To characterise the nearshore impact of the wave farm we define a series of impact indicators, including the Nearshore Impact (NI), the Maximum absolute Nearshore Impact (NImax) and the Relative Nearshore Impact (RNI). We find that increasing the farm-to-coast distance does not guarantee a reduction of the Maximum absolute Nearshore Impact, and that the distance influences the location of the point of occurrence of the maximum impact along the coast. © 2014 Elsevier Ltd.

Acosta E.,University of Santiago de Compostela
Optics Communications | Year: 2011

Certain optical aberrations of imaging systems yield low resolution images. Wavefront coding has proven to minimise this problem by means of hybrid optical-digital imaging systems. The optical part usually involves a phase plate described in terms of cubic polynomials whose shape is a linear combination of (x3 + y3) and (x2y + xy2). Optimization is achieved by seeking the most appropriate linear combination with respect to the optical system's constraints. Here, we propose the shape of two pairs of phase plates such that by means of relative rotations they allow for variation of the linear combination of the cubic terms. This will enable adaptive optimization of the cubic phase to the optical system's constraints when these vary in time. Results will be illustrated with numerical simulations. © 2011 Elsevier B.V. All rights reserved.

Campelo F.,University of Coimbra | Garcia-Gonzalez I.,University of Santiago de Compostela | Nabais C.,University of Coimbra
Dendrochronologia | Year: 2012

In this paper, we present the package detrendeR, a Graphical User Interface to facilitate the visualization and analysis of dendrochronological data, using the R computing environment. This package offers an easy way to perform most of the traditional tasks in dendrochronology: detrending, chronology building and graphical presentation of time series. The advantage of detrendeR, compared with the program ARSTAN, is the graphical interface that provides the user with an easy way to use R language, rich in graphics and handling routines, with no need to type commands. The detrendeR uses a simple and familiar dialog-box interface and it can read Tucson decadal-format files (*.rwl and *.crn) as well as plain text files. In addition, detrendeR has the ability to test temporal changes of the common signal using moving intervals. The detrendeR should make it easier to perform detrending and chronology building of tree-ring series, taking advantage of the R statistical programming environment. © 2011 Istituto Italiano di Dendrocronologia.

Baselga A.,University of Santiago de Compostela | Lobo J.M.,CSIC - National Museum of Natural Sciences | Svenning J.-C.,University of Aarhus | Araujo M.B.,CSIC - National Museum of Natural Sciences | Araujo M.B.,University of Evora
Journal of Biogeography | Year: 2012

Aim Do species range shapes follow general patterns? If so, what mechanisms underlie those patterns? We show for 11,582 species from a variety of taxa across the world that most species have similar latitudinal and longitudinal ranges. We then seek to disentangle the roles of climate, extrinsic dispersal limitation (e.g. barriers) and intrinsic dispersal limitation (reflecting a species' ability to disperse) as constraints of species range shape. We also assess the relationship between range size and shape. Location Global. Methods Range shape patterns were measured as the slope of the regression of latitudinal species ranges against longitudinal ranges for each taxon and continent, and as the coefficient of determination measuring the degree of scattering of species ranges from the 1:1 line (i.e. latitudinal range=longitudinal range). Two major competing hypotheses explaining species distributions (i.e. dispersal or climatic determinism) were explored. To this end, we compared the observed slopes and coefficients of determination with those predicted by a climatic null model that estimates the potential range shapes in the absence of dispersal limitation. The predictions compared were that species distribution shapes are determined purely by (1) intrinsic dispersal limitation, (2) extrinsic dispersal limitations such as topographic barriers, and (3) climate. Results Using this methodology, we show for a wide variety of taxa across the globe that species generally have very similar latitudinal and longitudinal ranges. However, neither neutral models assuming random but spatially constrained dispersal, nor models assuming climatic control of species distributions describe range shapes adequately. The empirical relationship between the latitudinal and longitudinal ranges of species falls between the predictions of these competing models. Main conclusions We propose that this pattern arises from the combined effect of macroclimate and intrinsic dispersal limitation, the latter being the major determinant among restricted-range species. Hence, accurately projecting the impact of climate change onto species ranges will require a solid understanding of how climate and dispersal jointly control species ranges. © 2011 Blackwell Publishing Ltd.

Iglesias Diz J.L.,University of Santiago de Compostela
Pediatria Integral | Year: 2013

Adolescence is the period that begins with the onset of puberty and finishes at the conclusion of growth. While the puberty is a physiologic change, adolescence is favored by the lifestyle of developed countries. Changes happen in a short period of time and involve physical, psychological and social events. The observed changes depend on three hormonal axes: hypothalamic-pituitarygonadal axis, hypothalamic-pituitary-adrenal axis and growth hormone axis. In the adolescence, psycho-social task include: achieve independence from parents, peers relationship, increase the importance of body image and identity development. Although adolescence has historically been defined as a period of extreme instability, many teenagers survive without difficulties.

Villasante S.,University of Santiago de Compostela
Marine Policy | Year: 2010

This paper provides a global analysis of recent trends in the EU fishing fleet. Analysis of the capital productivity, labour rates, and economic benefits of the fleet revealed that considerable replacement of fishermen by better technology and well-equipped vessels occurred between 1990 and 2006. The analysis confirms that the Common Fisheries Policy (CFP) has been ineffective in reducing fishing capacity. In addition, the changes in capacity that occurred in this time interval differed among the different sectors of the fleet. Some members of the high sea fishing fleet increased their capacity (range 11-57%), and the deep-sea sector, which has greater tonnage and fishing power, increased its fishing capacity by 34-44%. These results confirm the ineffectiveness of the CFP in reducing overcapacity and illustrate the continuing threat of overcapacity to the long-term sustainability of fishery resources. © 2009 Elsevier Ltd. All rights reserved.

Rissech C.,University of Barcelona | Lopez-Costas O.,University of Santiago de Compostela | Lopez-Costas O.,University of Granada | Turbon D.,University of Barcelona
International Journal of Legal Medicine | Year: 2013

The goal of the present study is to examine cross-sectional information on the growth of the humerus based on the analysis of four measurements, namely, diaphyseal length, transversal diameter of the proximal (metaphyseal) end of the shaft, epicondylar breadth and vertical diameter of the head. This analysis was performed in 181 individuals (90 â™" and 91 ♀) ranging from birth to 25 years of age and belonging to three documented Western European skeletal collections (Coimbra, Lisbon and St. Bride). After testing the homogeneity of the sample, the existence of sexual differences (Student's t- and Mann-Whitney U-test) and the growth of the variables (polynomial regression) were evaluated. The results showed the presence of sexual differences in epicondylar breadth above 20 years of age and vertical diameter of the head from 15 years of age, thus indicating that these two variables may be of use in determining sex from that age onward. The growth pattern of the variables showed a continuous increase and followed first- and second-degree polynomials. However, growth of the transversal diameter of the proximal end of the shaft followed a fourth-degree polynomial. Strong correlation coefficients were identified between humeral size and age for each of the four metric variables. These results indicate that any of the humeral measurements studied herein is likely to serve as a useful means of estimating sub-adult age in forensic samples. © 2012 Springer-Verlag.

Benincasa P.,University of Santiago de Compostela | Benincasa P.,Autonomous University of Madrid
International Journal of Modern Physics A | Year: 2014

We review some recent developments in the understanding of field theories in the perturbative regime. In particular, we discuss the notions of analyticity, unitarity and locality, and therefore the singularity structure of scattering amplitudes in general interacting theories. We describe their tree-level structure and their on-shell representations, as well as the links between the tree-level structure itself and the structure of the loop amplitudes. Finally, we describe the on-shell diagrammatics recently proposed both on general grounds and in the remarkable example of planar supersymmetric theories. © 2014 World Scientific Publishing Company.

Fernandez-Ramos A.,University of Santiago de Compostela
Journal of Chemical Physics | Year: 2013

This work presents an accurate way for calculating partition functions of strongly coupled hindered rotors in two dimensions. The two-dimensional torsional potential is generated from electronic structure calculations and fitted to Fourier series. The kinetic energy includes off-diagonal terms which are allowed to vary with the torsional angles, and these terms were also fitted to Fourier series. The resulting Hamiltonian leads to a coupled Schrödinger equation which was solved by the variational method. Therefore, the final two-dimensional non-separable (2D-NS) partition function incorporates coupling terms in both the kinetic and the potential energy. The methodology has been tested for propane, methyl formate, and a hydrogen abstraction transition state from propanone by the OH radical. How to incorporate the 2D-NS partition function in the total vibrational-rotational partition function is also discussed. © 2013 American Institute of Physics.

Gutierrez E.,University of Santiago de Compostela
International Journal of Eating Disorders | Year: 2013

Activity-based anorexia (ABA) is an analogous animal model of anorexia nervosa where food-restricted rats develop excessive running activity when given free access to a running wheel; their body weight sharply decreases, and finally self-starvation and death ensue unless animals are removed from the experimental conditions. The parallel of this animal model with major signs in the human disorder has been the focus of much attention from researchers and clinicians as a platform for translational research. The paper reviews the historical antecedents of ABA, research characterizing its occurrence, and its main limitations and strengths as a model of AN. As a symptomatic model of AN, the ABA model can provide clinicians with innovative and alternative routes for improving the treatment of AN. © 2013 by Wiley Periodicals, Inc. (Int J Eat Disord 2013) Copyright © 2013 Wiley Periodicals, Inc.

Elander D.,Tata Institute of Fundamental Research | Gaillard J.,University of Swansea | Nunezb C.,University of Santiago de Compostela | Piaib M.,Max Planck Institute for Physics
Journal of High Energy Physics | Year: 2011

We construct explicitly a new class of backgrounds in type-IIB supergravity which generalize the baryonic branch of Klebanov-Strassler. We apply a solution-generating technique that, starting from a large class of solutions of the wrapped-D5 system, yields the new solutions, and then proceed to study in detail their properties, both in the IR and in the UV. We propose a simple intuitive field theory interpretation of the rotation procedure and of the meaning of our new solutions within the Papadopoulos-Tseytlin ansatz, in particular in relation to the duality cascade in the Klebanov-Strassler solution. The presence in the field theory of different VEVs for operators of dimensions 2, 3 and 6 suggests that this is an important step towards the construction of the string dual of a genuinely multi-scale (strongly coupled) dynamical model. © SISSA 2011.

Moreda-Pineiro J.,University of La Coruna | Moreda-Pineiro A.,University of Santiago de Compostela
TrAC - Trends in Analytical Chemistry | Year: 2015

Sorbent and solvent microextraction techniques, mainly solid-phase microextraction, stir-bar sorptive extraction, single-drop microextraction, dispersive liquid-liquid microextraction, and hollow-fiber liquid-phase microextraction, are well-established, environment-friendly procedures for treating a wide range of samples when isolating organic and inorganic targets. Recently, microextraction techniques combined with other sample pre-treatments were shown to be excellent approaches for improving target isolation, and, thus, for enhancing the quality of the whole analysis. This review therefore deals with recent advances when coupling several microextraction techniques as sample pre-treatment methods for liquid and solid environmental and biological materials. This review includes an updated overview on combined microextraction techniques (design and operational requirements), the advantages and the disadvantages of current developments, and future prospects. © 2015 Elsevier B.V.

Villasante S.,University of Santiago de Compostela | Villasante S.,Royal Swedish Academy Of Sciences
Marine Policy | Year: 2012

In Europe, 88% of fish stocks are being fished beyond Maximum Sustainable Yield and 30% of stocks are outside of biological limits. The blue whiting fishery is also following a consistent trend of a declining, and the EU recently adopted a 93% quota decrease for this species. Despite the abundant literature related to genetic aspects of population structure of aquatic resources, few studies have specifically addressed the link between fisheries management and population genetics. Given potential differences in the behavior of different subpopulations, population genetics has great relevance in the correct interpretation of the evolution of stocks. Ignoring the congruence of spatial scales between the population structure of fish species and management units can result in reduced productivity and local reduction of populations. This paper adopts the framework of resilience to explore the social-ecological feedbacks between unobserved genetic diversity and human dimension of the blue whiting fishery in Galician coastal communities due to the mismanagement of the fishery in the EU. The results presented here suggest that there is considerable evidence that the currently used management unit is inconsistent with the recent growth and genetic differences observed. The results also reveal that based on the evidence currently available and in accordance with the precautionary principle, the stocks of blue whiting in Northern and Southern ICES areas should be treated as separate in the Northeast Atlantic Ocean. The results obtained indicate that unobserved genetic diversity of the fishery can lead to an equivocal reduction of fishing quotas in the Southern area. Finally, the paper also shows that the total economic losses resulting from the 93% quota decrease of the species, which includes effects on the rest of the Galician economy, is 40,081,636 Euros per year. The next Common Fishery Policy Reform offers a great opportunity to reverse the current unsustainable path of the fishery and to accept humans as a component of this marine social-ecological system. © 2012 Elsevier Ltd.

Baselga A.,University of Santiago de Compostela
Global Ecology and Biogeography | Year: 2012

Aim Beta diversity can be partitioned into two components: dissimilarity due to species replacement and dissimilarity due to nestedness (Baselga, 2010, Global Ecology and Biogeography, 19, 134-143). Several contributions have challenged this approach or proposed alternative frameworks. Here, I review the concepts and methods used in these recent contributions, with the aim of clarifying: (1) the rationale behind the partitioning of beta diversity into species replacement and nestedness-resultant dissimilarity, (2) how, based on this rationale, numerators and denominators of indices have to match, and (3) how nestedness and nestedness-resultant dissimilarity are related but different concepts. Innovation The rationale behind measures of species replacement (turnover) dictates that the number of species that are replaced between sites (numerator of the index) has to be relativized with respect to the total number of species that could potentially be replaced (denominator). However, a recently proposed partition of Jaccard dissimilarity fails to do this. In consequence, this partition underestimates the contribution of species replacement and overestimates the contribution of richness differences to total dissimilarity. I show how Jaccard dissimilarity can be partitioned into meaningful turnover and nestedness components, and extend these new indices to multiple-site situations. Finally the concepts of nestedness and nestedness-resultant dissimilarity are discussed. Main conclusions Nestedness should be assessed using consistent measures that depend both on paired overlap and matrix filling, e.g. NODF, whereas beta-diversity patterns should be examined using measures that allow the total dissimilarity to be separated into the components of dissimilarity due to species replacement and dissimilarity due to nestedness. In the case of multiple-site dissimilarity patterns, averaged pairwise indices should never be used because the mean of the pairwise values is unable to accurately reflect the multiple-site attributes of dissimilarity. © 2012 Blackwell Publishing Ltd.

Hollowood T.J.,University of Swansea | Miramontesb J.L.,University of Santiago de Compostela
Journal of High Energy Physics | Year: 2010

The motion of strings on symmetric space target spaces underlies the inte- grability of the AdS/CFT correspondence. Although these theories, whose excitations are giant magnons, are non-relativistic they are classically equivalent, via the Polhmeyer reduc- tion, to a relativistic integrable field theory known as a symmetric space sine-Gordon theory. These theories can be formulated as integrable deformations of gauged WZW models. In this work we consider the class of symmetric spaces CP n+1 and solve the corresponding generalized sine-Gordon theories at the quantum level by finding the exact spectrum of topological solitons, or kinks, and their S-matrix. The latter involves a trignometric solu- tion of the Yang-Baxer equation which exhibits a quantum group symmetry with a tower of states that is bounded, unlike for magnons, as a result of the quantum group deformation parameter q being a root of unity. We test the S-matrix by taking the semi-classical limit and comparing with the time delays for the scattering of classical solitons. We argue that the internal CP n-1 moduli space of collective coordinates of the solitons in the classical theory can be interpreted as a q-deformed fuzzy space in the quantum theory. We analyse the n = 1 case separately and provide a further test of the S-matrix conjecture in this case by calculating the central charge of the UV CFT using the thermodynamic Bethe Ansatz. © SISSA 2010.

Gomez-Carballa A.,University of Santiago de Compostela
PloS one | Year: 2012

The Late Glacial Maximum (LGM), ∼20 thousand years ago (kya), is thought to have forced the people inhabiting vast areas of northern and central Europe to retreat to southern regions characterized by milder climatic conditions. Archaeological records indicate that Franco-Cantabria might have been the major source for the re-peopling of Europe at the beginning of the Holocene (11.5 kya). However, genetic evidence is still scarce and has been the focus of an intense debate. Based on a survey of more than 345,000 partial control region sequences and the analysis of 53 mitochondrial DNA (mtDNA) genomes, we identified an mtDNA lineage, HV4a1a, which most likely arose in the Franco-Cantabrian area about 5.4 kya and remained confined to northern Iberia. The HV4a1a lineage and several of its younger branches reveal for the first time genetic continuity in this region and long-term episodes of isolation. This, in turn, could at least in part explain the unique linguistic and cultural features of the Basque region.

Martin-Pastor M.,University of Santiago de Compostela
Journal of Agricultural and Food Chemistry | Year: 2014

A 1D NMR singlet filtered experiment (s-filter) is presented for the clean editing of singlets peaks in crowded 1H NMR spectra. The experiment affords a clean editing of singlet peaks and weak coupled signals ( nJHH < 3 Hz), while the remaining multiplets peaks are strongly attenuated to a factor over 90% of its original intensity. The experiment provided a useful simplification of the typically congested 1H NMR spectra of foodstuffs, and the edited signals retained most of the sensitivity and quantitativity. The versatility of the s-filter scheme permitted its easy incorporation as excitation building block into other 1D and 2D experiments, providing a further editing of the singlet responses. The combination of the 1D s-filter experiment and difference spectroscopy provided a 1D reverse singlet filtered experiment (s-filterrev) for the clean editing of multiplet peaks and strong suppression of singlets. The experiments proposed could be valuable to facilitate the detection and/or quantification of target compounds in complex mixtures of metabolites. © 2014 American Chemical Society.

Ramos V.,University of Santiago de Compostela | Iglesias G.,University of Plymouth
International Journal of Green Energy | Year: 2014

Arousa, a natural reserve island facing the Atlantic Ocean, aims to reduce its dependency on conventional energy sources. This work has two main objectives: to investigate the potential of wind power and to study the implementation of a wind farm in Arousa. The resource is characterized by its narrow range of directions (SW and NE in winter and summer, respectively) and marked monthly and hourly variability. The windiest months are in summer (July and August) and winter (February and March). Regarding the hourly variability, there occur two periods of higher wind speed: the afternoon (from 1 to 5 pm) and late evening (from 8 pm to midnight). Rayleigh and Weibull distributions are fitted to the annual and monthly data series. While the Rayleigh distribution tends to overestimate slightly the resource, its Weibull counterpart provides a good fit. Overall, a substantial wind resource exists in Arousa. On these grounds, the viability and implementation of a wind farm are analyzed, taking the Vestas V82-1.65 MW turbine as a reference. Performance parameters (capacity factor, availability factor, and efficiency) are computed on annual and monthly bases. The results prove that a wind farm with six turbines is capable of fulfilling the electricity demand of the island extrapolated 25 years into the future, providing an adequate storage solution (e.g., hydrogen). © 2014 Taylor and Francis Group, LLC.

A simple and rapid continuous manifold for sample dissolution based on ultrasound energy is evaluated for flow injection determination of calcium and magnesium in pharmaceutical tablets by flame atomic absorption spectrometry. Several parameters that could influence the dissolution process were evaluated by Plackett-Burman experimental designs. The obtained results showed that samples were easily dissolved with ultrapure water at room temperature at a flow-rate of 6 mL min-1 under the action of ultrasound energy during 30 seconds. The analytical method was characterized and the limit of detection and limit of quantification for the two metals were 2.8 and 9.5 mg g -1 for Ca and 7.5 and 25 μg g-1 for Mg, respectively. The sampling frequency of the system was about 50 samples per hour, with repeatability, expressed as relative standard deviation, in the range 0.5 and 3.0% for both metals. The proposed methodology was successfully applied to determine calcium and magnesium in multivitamin tablets.

Rodriguez-Sanz A.A.,Facultade de Ciencias | Cabaleiro-Lago E.M.,Facultade de Ciencias | Rodriguez-Otero J.,University of Santiago de Compostela
Organic and Biomolecular Chemistry | Year: 2014

A computational study has been carried out in complexes formed by pyrrolidinium cation and aromatic units present in amino acid side chains. The interaction is stronger with indole (-21.9 kcal mol-1 at the CCSD(T) complete basis set level) than with phenol (-17.4 kcal mol-1) or benzene (-16.1 kcal mol-1). Most stable structures show a N-H⋯π contact between pyrrolidinium cation and the phenyl ring of the three aromatic species, except in phenol complexes where the most stable minimum shows a N-H⋯O hydrogen bond. In phenol and indole complexes, secondary contacts are established between the C-H groups of the carbon skeleton of pyrrolidinium and the aromatic rings or hydroxyl oxygen, being the main reason for the enhanced stability with respect to benzene, where these contacts are not possible. The interaction is mainly controlled by electrostatics, but contributions from induction and dispersion are also significant, especially the latter in indole complexes. These three attractive contributions increase their intensity when going from benzene to phenol and indole. Microhydration effects have been estimated by including up to three water molecules in the complexes. In monohydrated pyrrolidinium⋯benzene complex the most stable structure shows the water molecule coordinated to the cation without interacting with the ring. In phenol and indole, otherwise, the water molecule interacts with both the cation and the aromatic species, forming a cyclic hydrogen bond pattern π(phenyl)⋯H-N-H⋯O-H⋯X (X = π, O). This pattern is also present among the most stable structures found for complexes with two and three water molecules, though a variety of almost isoenergetic minima showing different hydrogen bond patterns have been found. Water molecules remove the stability differences between phenol and indole complexes, which already with two water molecules show similar stabilities, though around 5 kcal mol -1 larger than benzene ones. This journal is © the Partner Organisations 2014.

De Planell-Saguer M.,Columbia University | Rodicio M.C.,University of Santiago de Compostela
Clinical Biochemistry | Year: 2013

MicroRNAs (miRNA) are short non-coding RNA molecules that regulate gene expression. miRNAs profiles are specific for cell lineages and tissues, and their changes reflect pathological processes. This fact introduces the possibility of their use in diagnostics. The application of miRNAs in diagnostics is critically dependent on the establishment of miRNA profiles that can discriminate patients from normal healthy individuals with good sensitivity and specificity and on the development of methods for their accurate and high-throughput quantification. In this review, we present an overview of some of the different techniques and methods currently used to detect miRNAs. We focus on methods that can be employed in routine clinic diagnostics indicating their advantages as well as their shortcomings, with special attention being paid to the most innovative ones. Since disease-specific miRNAs can be found in blood serum, we also present emerging methods for the detection of circulating miRNAs as a way of fast, reliable and non-invasive diagnostic. © 2013 The Canadian Society of Clinical Chemists.

Zurita P.,University of Santiago de Compostela
Nuclear and Particle Physics Proceedings | Year: 2016

In recent years the physics of heavy-ion collisions has seen a phenomenal increase of interest from both the experimental and theoretical particle physics community. In particular the field has been pushed forward by the proton-lead and lead-lead programs at the LHC, given the fact that they can provide information on both cold nuclear matter effects and the quark-gluon plasma. Unfortunately a clear distinction between hot and cold nuclear effects is hard to achieve at the LHC, and thus in the last decade the construction of electron-ion colliders have been proposed in order to shed light on this matter. In this talk we explore some of the possibilities for the study of heavy-ions that such facilities offer and compare with the potential of the LHC. Specifically, we focus on the proposed Large Hadron-electron Collider facility at CERN. © 2015 Elsevier B.V.

Colao A.,University of Naples Federico II | Boscaro M.,Marche Polytechnic University | Ferone D.,University of Genoa | Casanueva F.F.,University of Santiago de Compostela | Casanueva F.F.,CIBER ISCIII
Endocrine | Year: 2014

Cushing's disease is a rare chronic disease caused by a pituitary adenoma, which leads to excess secretion of adrenocorticotropic hormone (ACTH). The over-production of ACTH leads to hyperstimulation of the adrenal glands and a chronic excess of cortisol, resulting in the signs and symptoms of a severe clinical state (Cushing's syndrome) that leads to significant morbidity, negative impacts on the patient's quality of life, and, if untreated, increased mortality. The management of patients with Cushing's disease is complicated by the heterogeneity of the condition, with signs and symptoms that overlap with those of other diseases, and high subclinical incidence rates. Controversies surrounding the tests used for screening and identifying patients with Cushing's disease add to the challenge of patient management. Surgical intervention to remove the adenoma is the first-line treatment for patients with Cushing's disease, but medical therapies are useful in patients who relapse or are unsuitable for surgery. The recent introduction of pasireotide, the first pituitary-directed medical therapy, expands the number of treatment options available for patients with Cushing's disease. This state-of-the-art review aims to provide an overview of the most recent scientific research and clinical information regarding Cushing's disease. Continuing research into improving the diagnosis and treatment of Cushing's disease will help to optimize patient management. © 2014 Springer Science+Business Media.

Egeland T.,Norwegian University of Life Sciences | Salas A.,University of Santiago de Compostela
PLoS ONE | Year: 2011

Background: Mitochondrial DNA (mtDNA) variation is commonly analyzed in a wide range of different biomedical applications. Cases where more than one individual contribute to a stain genotyped from some biological material give rise to a mixture. Most forensic mixture cases are analyzed using autosomal markers. In rape cases, Y-chromosome markers typically add useful information. However, there are important cases where autosomal and Y-chromosome markers fail to provide useful profiles. In some instances, usually involving small amounts or degraded DNA, mtDNA may be the only useful genetic evidence available. Mitochondrial DNA mixtures also arise in studies dealing with the role of mtDNA variation in tumorigenesis. Such mixtures may be generated by the tumor, but they could also originate in vitro due to inadvertent contamination or a sample mix-up. Methods/Principal Findings: We present the statistical methods needed for mixture interpretation and emphasize the modifications required for the more well-known methods based on conventional markers to generalize to mtDNA mixtures. Two scenarios are considered. Firstly, only categorical mtDNA data is assumed available, that is, the variants contributing to the mixture. Secondly, quantitative data (peak heights or areas) on the allelic variants are also accessible. In cases where quantitative information is available in addition to allele designation, it is possible to extract more precise information by using regression models. More precisely, using quantitative information may lead to a unique solution in cases where the qualitative approach points to several possibilities. Importantly, these methods also apply to clinical cases where contamination is a potential alternative explanation for the data. Conclusions/Significance: We argue that clinical and forensic scientists should give greater consideration to mtDNA for mixture interpretation. The results and examples show that the analysis of mtDNA mixtures contributes substantially to forensic casework and may also clarify erroneous claims made in clinical genetics regarding tumorigenesis. © 2011 Egeland, Salas.

Adam C.,University of Santiago de Compostela | Haberichter M.,University of Kent | Wereszczynski A.,Jagiellonian University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2016

There exists, in general, no unique definition of the size (volume, area, etc., depending on dimension) of a soliton. Here we demonstrate that the geometric volume (area etc.) of a soliton is singled out in the sense that it exactly coincides with the thermodynamical or continuum-mechanical volume. In addition, this volume may be defined uniquely for rather arbitrary solitons in arbitrary dimensions. © 2016 The Authors.

Ramallo M.V.,University of Santiago de Compostela
Nanoscale Research Letters | Year: 2013

We present model equations for the trapping and accumulation of particles in a cylindrical channel with nanostructured inner walls when a fluid passes through, carrying a moderate load of impurities. The basic ingredient of the model is the introduction of a phenomenological 'effective-charge density' of the walls, related to the electrical charges exposed in the nanotexture. The effective charge is gradually reduced as the flow runs through the channel and the trapped impurities cover the internal walls. Based on the proposed equations, the position and time dependence of the areal density of trapped impurities, and the filtration performance, may be calculated. It is proposed that experimentally testing these results may help to understand the enhanced trapping capability observed in many diverse nanotextured channel structures. © 2013 Ramallo; licensee Springer.

Gomez R.,Institute of Cellular Medicine | Villalvilla A.,Autonomous University of Madrid | Largo R.,Autonomous University of Madrid | Gualillo O.,University of Santiago de Compostela | Herrero-Beaumont G.,Autonomous University of Madrid
Nature Reviews Rheumatology | Year: 2015

Osteoarthritis (OA), the most common rheumatic disease, is characterized by joint-space narrowing due to progressive cartilage degradation and alterations in subchondral bone and the synovial membrane. These articular disturbances can have severe consequences, including pain, disability and loss of joint architectural integrity. Although the aetiology of OA is not understood, chondrocyte-mediated inflammatory responses triggered by the activation of innate immune receptors by damage-associated molecules are thought to be involved. In this Review, we examine the relationship between Toll-like receptor 4 (TLR4) and OA in cartilage as well as in other OA-affected tissues, such as subchondral bone and synovium. We also discuss the different TLR4 agonists associated with OA and their effects in joint tissues. Finally, we describe existing and novel strategies that might be used to develop TLR4-specific disease-modifying OA drugs (DMOADs). © 2015 Macmillan Publishers Limited.

Carlson W.,University of Witwatersrand | De Mello Koch R.,University of Witwatersrand | De Mello Koch R.,Stellenbosch Institute for Advanced Studies | Lin H.,University of Santiago de Compostela
Journal of High Energy Physics | Year: 2011

In this article we study operators with a dimension δ ∼ O(N) and show that simple analytic expressions for the action of the dilatation operator can be found. The operators we consider are restricted Schur polynomials. There are two distinct classes of operators that we consider: operators labeled by Young diagrams with two long columns or two long rows. The main complication in working with restricted Schur polynomials is in building a projector from a given Sn+m irreducible representation to an Sn× Sm irreducible representation (both specified by the labels of the restricted Schur polynomial). We give an explicit construction of these projectors by reducing it to the simple problem of addition of angular momentum in ordinary non-relativistic quantum mechanics. The diagonalization of the dilatation operator reduces to solving three term recursion relations. The fact that the recursion relations have only three terms is a direct consequence of the weak mixing at one loop of the restricted Schur polynomials. The recursion relations can be solved exactly in terms of symmetric Kravchuk polynomials or in terms of Clebsch-Gordan coefficients. This proves that the dilatation operator reduces to a decoupled set of harmonic oscillators and therefore it is integrable. © SISSA 2011.

Soengas R.G.,University of La Coruna | Estevez A.M.,University of Santiago de Compostela
Synlett | Year: 2010

A very simple, safe and powerful method for the hydroxymethylation of 2-bromoesters and lactones under anhydrous conditions that avoids the use of gaseous formaldehyde is described. Moreover, under these conditions, bromonitroalkanes were converted into the corresponding α- monohydroxymethylated nitroalkanes, which are precursors of the corresponding α-amino acids. Considering the easy transformation of ketones into bromonitroalkanes, this represents a method for the formal synthesis of α-amino acids from ketones. © Georg Thieme Verlag Stuttgart New York.

Vazquez A.,Laboratoire Of Linformatique Du Parallelisme | Antelo E.,University of Santiago de Compostela | Montuschi P.,Polytechnic University of Turin
IEEE Transactions on Computers | Year: 2010

The new generation of high-performance decimal floating-point units (DFUs) is demanding efficient implementations of parallel decimal multipliers. In this paper, we describe the architectures of two parallel decimal multipliers. The parallel generation of partial products is performed using signed-digit radix-10 or radix-5 recodings of the multiplier and a simplified set of multiplicand multiples. The reduction of partial products is implemented in a tree structure based on a decimal multioperand carry-save addition algorithm that uses unconventional (non BCD) decimal-coded number systems. We further detail these techniques and present the new improvements to reduce the latency of the previous designs, which include: optimized digit recoders for the generation of 2n-tuples (and 5-tuples), decimal carry-save adders (CSAs) combining different decimal-coded operands, and carry-free adders implemented by special designed bit counters. Moreover, we detail a design methodology that combines all these techniques to obtain efficient reduction trees with different area and delay trade-offs for any number of partial products generated. Evaluation results for 16-digit operands show that the proposed architectures have interesting area-delay figures compared to conventional Booth radix-4 and radix - 8 parallel binary multipliers and outperform the figures of previous alternatives for decimal multiplication. © 2006 IEEE.

Riesco Munoz G.,University of Santiago de Compostela | Remacha Gete A.,Technical University of Madrid
Journal of Materials in Civil Engineering | Year: 2012

The purpose of the study was to propose accurate models for predicting bending strength that are valid for a wide range of beam qualities. For the study, 26 European oaks (Quercus robur L.) were felled in northwestern Spain, where most of the oak stands in the country are located. The trees were sawn, and a sample of quarter-sawn planks was selected. Planed and edged specimens (5×10×200 cm) were tested to obtain the modulus of rupture (MOR) in axial direction bending, the modulus of elasticity (MOE), density, moisture content, and size of defects. The MOR was correlated with the MOE and with maximum edge knot diameter. The correlation was not high enough to justify construction of a predictive model of mechanical behavior on the basis of maximum knot size in the piece. The analyses enabled development of a model for predicting MOR, with MOE as the only predictor variable (R 2=0.65; bias=0.6%). © 2012 American Society of Civil Engineers.

Cameselle-Teijeiro J.,University of Santiago de Compostela
Virchows Archiv : an international journal of pathology | Year: 2014

The present study describes in depth a case of Riedel thyroiditis (RT) to clarify its pathogenesis and its putative inclusion in the spectrum of IgG4-related disease. We report the clinicopathological, immunohistochemical, and ultrastructural features of a case of RT in a 39-year-old white Spanish woman, admitted with a hard goiter and cold nodule in the left thyroid lobe. This case represents 0.05 % of a series of 1,973 consecutive thyroidectomies performed in our hospital. More than 80 % of the left thyroid lobe was effaced by fibrosis and inflammation (lymphocytes, 57 IgG4+ plasma cells per 1 high-power field, an IgG4/IgG ratio of 0.67, and eosinophils) with extension into the surrounding tissues and occlusive phlebitis. Immunostaining for podoplanin (D2-40) detected signs of increased lymphangiogenesis in the fibroinflammatory areas that were confirmed by electron microscopy. A strong, diffuse stain for podoplanin and transforming growth factor ß1 was also detected in the same areas. The increased number of lymphatic vessels in RT is reported for the first time. Our findings support the inclusion of RT within the spectrum of IgG4-related thyroid disease (IgG4-RTD). Although the etiology and physiopathology of IgG4-RTD still remain elusive, the results obtained in the present case suggest the participation of lymphatic vessels in the pathogenesis of RT.

Capella A.,University Paris - Sud | Ferreiro E.G.,University of Santiago de Compostela
European Physical Journal C | Year: 2012

The mid-rapidity charged particle multiplicities in pp and AA collisions at LHC energies are described in the framework of a generalized eikonal model with shadowing corrections incorporated in AA. We show that the pp data require a Pomeron intercept close to 1. 2, higher than the conventional one, close to 1.1. An s 0.11 energy dependence is obtained in the LHC range and beyond. The size and centrality dependence of the AA multiplicity at √{s} =2.76 TeV is reproduced and its energy dependence is predicted. © 2012 Springer-Verlag / Società Italiana di Fisica.

Paz M.M.,University of Santiago de Compostela
Bioorganic Chemistry | Year: 2013

The anticancer drug mitomycin C produces cytotoxic effects after being converted to a highly reactive bis-electrophile by a reductive activation, a reaction that a number of 1-electron or 2-electron oxidoreductase enzymes can perform in cells. Several reports in the literature indicate that ascorbic acid can modulate the cytotoxic effects of mitomycin C, either potentiating or inhibiting its effects. As ascorbic acid is a reducing agent that is known to be able to reduce quinones, it could be possible that the observed modulatory effects are a consequence of a direct redox reduction between mitomycin C and ascorbate. To determine if this is the case, the reaction between mitomycin C and ascorbate was studied using UV/Vis spectroscopy and LC/MS. We also studied the reaction of ascorbate with mitomycin A, a highly toxic member of the mitomycin family with a higher redox potential than mitomycin C. We found that ascorbate is capable to reduce mitomycin A efficiently, but it reduces mitomycin C rather inefficiently. The mechanisms of activation have been elucidated based on the kinetics of the reduction and on the analysis of the mitosene derivatives formed after the reaction. We found that the activation occurs by the interplay of three different mechanisms that contribute differently, depending on the pH of the reaction. As the reduction of mitomycin C by ascorbate is rather inefficiently at physiologically relevant pH values we conclude that the modulatory effect of ascorbate on the cytotoxicity of mitomycin C is not the result of a direct redox reaction and therefore this modulation must be the consequence of other biochemical mechanisms. © 2013 Elsevier Inc. All rights reserved.

Jokela N.,University of Helsinki | Jokela N.,Helsinki Institute of Physics | Ramallo A.V.,University of Santiago de Compostela | Ramallo A.V.,Instituto Galego Of Fisica Of Altas Enerxias Igfae
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

We study the collective excitations of holographic quantum liquids formed in the low energy theory living at the intersection of two sets of D-branes. The corresponding field theory dual is a supersymmetric Yang-Mills theory with massless matter hypermultiplets in the fundamental representation of the gauge group which generically live on a defect of the unflavored theory. Working in the quenched (probe) approximation, we focus on determining the universal properties of these systems. We analyze their thermodynamics, the speed of first sound, the diffusion constant, and the speed of zero sound. We study the influence of temperature, chemical potential, and magnetic field on these quantities, as well as on the corresponding collisionless/hydrodynamic crossover. We also generalize the alternative quantization for all conformally AdS4 cases and study the anyonic correlators. © 2015 American Physical Society.

Kaufman S.B.,Yale University | DeYoung C.G.,University of Minnesota | Gray J.R.,Yale University | Jimenez L.,University of Santiago de Compostela | And 2 more authors.
Cognition | Year: 2010

The ability to automatically and implicitly detect complex and noisy regularities in the environment is a fundamental aspect of human cognition. Despite considerable interest in implicit processes, few researchers have conceptualized implicit learning as an ability with meaningful individual differences. Instead, various researchers (e.g., Reber, 1993; Stanovich, 2009) have suggested that individual differences in implicit learning are minimal relative to individual differences in explicit learning. In the current study of English 16-17. year old students, we investigated the association of individual differences in implicit learning with a variety of cognitive and personality variables. Consistent with prior research and theorizing, implicit learning, as measured by a probabilistic sequence learning task, was more weakly related to psychometric intelligence than was explicit associative learning, and was unrelated to working memory. Structural equation modeling revealed that implicit learning was independently related to two components of psychometric intelligence: verbal analogical reasoning and processing speed. Implicit learning was also independently related to academic performance on two foreign language exams (French, German). Further, implicit learning was significantly associated with aspects of self-reported personality, including intuition, Openness to Experience, and impulsivity. We discuss the implications of implicit learning as an ability for dual-process theories of cognition, intelligence, personality, skill learning, complex cognition, and language acquisition. © 2010 Elsevier B.V.

Davila-Ibanez A.B.,University of Santiago de Compostela | Correa-Duarte M.A.,University of Vigo | Salgueirino V.,University of Vigo
Journal of Materials Chemistry | Year: 2010

Highly active and magnetically recoverable colloidal catalysts were synthesized assembling iron oxide and platinum nanoparticles by means of mesoporous silica that upholds them as a core-shell structured system. Conveniently, these composites present multiple magnetic cores gaining special relevance in the catalyst's recovery as responding to low magnetic fields. As a proof of concept, they were used to assess the retarded gold reduction in cetyltrimethylammonium bromide (CTAB) micelles, permitting to tune the gold reduction rate and therefore the production of spherical or anisotropic gold nanostructures. © 2010 The Royal Society of Chemistry.

Vilar S.,University of Santiago de Compostela | Costanzi S.,U.S. National Institute of Diabetes and Digestive and Kidney Diseases
Methods in Enzymology | Year: 2013

Receptor ensemble docking (RED) is an effective strategy to account for receptor flexibility in the course of a docking-based virtual screening campaign. Such an approach can be applied when multiple crystal structures of a receptor have been solved, but it can also be applied when only a single crystal structure is available. In this case, alternative structures can be generated from the latter by computational means and subsequently applied to RED. Here, we illustrate how such conformers can be generated by subjecting a crystal structure to Monte Carlo conformational searches. Through a controlled virtual screening experiment, we then show the applicability of such a strategy to the identification of ligands of the β2 adrenergic receptor, a G protein-coupled receptor activated by epinephrine. Requiring the availability of one crystal structure only, this strategy is applicable to all systems for which multiple experimentally elucidated structures are not available. © 2013 Elsevier Inc.

Carramolino-Cuellar E.,University of Valencia | Tomas I.,University of Santiago de Compostela | Jimenez-Soriano Y.,University of Valencia
Medicina Oral, Patologia Oral y Cirugia Bucal | Year: 2014

The components of the human body are closely interdependent; as a result, disease conditions in some organs or components can influence the development of disease in other body locations. The effect of oral health upon health in general has been investigated for decades by many epidemiological studies. In this context, there appears to be a clear relationship between deficient oral hygiene and different systemic disorders such as cardiovascular disease and metabolic syndrome. The precise relationship between them is the subject of ongoing research, and a variety of theories have been proposed, though most of them postulate the mediation of an inflammatory response. This association between the oral cavity and disease in general requires further study, and health professionals should be made aware of the importance of adopting measures destined to promote correct oral health. The present study conducts a Medline search with the purpose of offering an update on the relationship between oral diseases and cardiovascular diseases, together with an evaluation of the bidirectional relationship between metabolic syndrome and periodontal disease. Most authors effectively describe a moderate association between the oral cavity and cardiovascular diseases, though they also report a lack of scientific evidence that oral alterations constitute an independent cause of cardiovascular diseases, or that their adequate treatment can contribute to prevent such diseases. In the case of metabolic syndrome, obesity and particularly diabetes mellitus may be associated to an increased susceptibility to periodontitis. However, it is not clear whether periodontal treatment is able to improve the systemic conditions of these patients. © Medicina Oral S. L.

Pokhrel Y.N.,Rutgers University | Fan Y.,Rutgers University | Miguez-Macho G.,University of Santiago de Compostela | Yeh P.J.-F.,International Center for Water Hazard and Risk Management | Han S.-C.,NASA
Journal of Geophysical Research: Atmospheres | Year: 2013

We explore the mechanisms whereby groundwater influences terrestrial water storage (TWS) in the Amazon using GRACE observations and two contrasting versions of the LEAF-Hydro-Flood hydrological model: one with and the other without an interactive groundwater. We find that, first, where the water table is shallow as in northwestern Amazonia and floodplains elsewhere, subsurface stores (vadose zone and groundwater) are nearly saturated year-round, hence river and flooding dominate TWS variation; where the water table is deep as in southeastern Amazonia, the large subsurface storage capacity holds the infiltrated water longer before releasing it to streams, hence the subsurface storage dominates TWS variation. Second, over the whole Amazon, the subsurface water contribution far exceeds surface water contribution to total TWS variations. Based on LEAF-Hydro-Flood simulations, 71% of TWS change is from subsurface water, 24% from flood water, and 5% from water in river channels. Third, the subsurface store includes two competing terms, soil water in the vadose zone and groundwater below the water table. As the water table rises, the length of vadose zone is shortened and hence the change in groundwater store is accompanied by an opposite change in soil water store resulting in their opposite phase and contributions to total TWS. We conclude that the inclusion of a prognostic groundwater store and its interactions with the vadose zone, rivers, and floodplains in hydrological simulations enhances seasonal amplitudes and delays seasonal peaks of TWS anomaly, leading to an improved agreement with GRACE observations. ©2013. American Geophysical Union. All Rights Reserved.

Garcia-Tunon E.,University of Santiago de Compostela
Acta crystallographica. Section B, Structural science | Year: 2012

We have synthesized large chlorapatite [ClAp, Ca(5)(PO(4))(3)Cl(x)(OH)(1-x), where x = 1] single crystals using the molten salt method. We have corroborated that the hexagonal symmetry P6(3)/m describes the crystal structure best, even though the crystals are synthetic and stoichiometric. Moreover, we have performed several thermal treatments on these ClAp crystals, generating new single crystals in the apatite system [Ca(5)(PO(4))(3)Cl(x)(OH)(1-x), where x ≤ 1], where the chloride anions (Cl(-)) were systematically substituted by hydroxyl anions (OH(-)). These new single crystals were methodically characterized by powder and single-crystal X-ray diffraction (SXRD), scanning electron microscopy (SEM), Fourier transform-IR spectroscopy (FT-IR), and energy-dispersive X-ray spectroscopy (EDS). We have discovered a previously unreported OH(-) inclusion site substituting the Cl(-) anion during the ion-exchanging process. Finally, we evaluated the atomic rearrangements of the other species involved in the structure. These movements are associated with ionic exchange, which can be justified from an energetic point of view. We also found a novel phase transformation at high temperature. When the crystals are heated over 1753 K the apatite system evolves to a less ordered monoclinic structure, in which the complete loss of the species in the anionic channel (Cl(-), OH(-)) has been confirmed.

Gonzalez-Bello C.,University of Santiago de Compostela
Future Medicinal Chemistry | Year: 2015

Type I dehydroquinase (DHQ1) is a class I aldolase enzyme that catalyzes the reversible dehydration of 3-dehydroquinic acid to form 3-dehydroshikimic acid by multistep mechanism that involves the formation of Schiff-base species. DHQ1 is present in plants and several bacterial sources but it does not have any counterpart in human cells. It has been suggested that DHQ1 may act as a virulence factor in vivo and therefore a promising target in the search for new antivirulence agents to combat widespread antibiotic resistance. This review covers recent progress in the structure-based design and chemical modifications caused by selective irreversible inhibitors. Computational studies aimed at understanding the experimentally obtained covalent modifications and inhibitory potencies of these inhibitors are also described. © 2015 Future Science Ltd.

Higes M.,Centro Apicola Regional CAR | Meana A.,Complutense University of Madrid | Bartolome C.,University of Santiago de Compostela | Botias C.,Centro Apicola Regional CAR | Martin-Hernandez R.,Institute Recursos Humanos para la Ciencia y la Tecnologia INCRECYT
Environmental Microbiology Reports | Year: 2013

The worldwide beekeeping sector has been facing a grave threat, with losses up to 100-1000 times greater than those previously reported. Despite the scale of this honey bee mortality, the causes underlying this phenomenon remain unclear, yet they are thought to be multifactorial processes. Nosema ceranae, a microsporidium recently detected in the European bee all over the world, has been implicated in the global phenomenon of colony loss, although its role remains controversial. A review of the current knowledge about this pathogen is presented focussing on discussion related with divergent results, trying to analyse the differences specially based on different methodologies applied and divisive aspects on pathology while considering a biological or veterinarian point of view. For authors, the disease produced by N.ceranae infection cannot be considered a regional problem but rather a global one, as indicated by the wide prevalence of this parasite in multiple hosts. Not only does this type of nosemosis causes a clear pathology on honeybees at both the individual and colony levels, but it also has significant effects on the production of honeybee products. Journal compilation © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

Azzari C.,University of Florence | Martinon-Torres F.,University of Santiago de Compostela | Martinon-Torres F.,Healthcare Research Institute of Santiago | Schmitt H.-J.,Pfizer | Dagan R.,Ben - Gurion University of the Negev
Pediatric Infectious Disease Journal | Year: 2014

Since the introduction of 7-valent pneumococcal conjugate vaccine (PCV7), PCVs with extended coverage have become available, and there is emerging global evidence that these vaccines, in particular PCV13, have further reduced rates of invasive pneumococcal disease compared with PCV7. The present article aims to address emerging topics related to PCV13 use in routine clinical practice; specifically: (1) the potential role of high-valent PCVs in reducing pneumococcal disease burden; (2) the impact of PCVs on nasopharyngeal carriage and how this may contribute to reductions in otitis media and pneumonia, as well as the prevalence of resistant pneumococcal strains; (3) new PCV13 indications and (4) importance of schedule adherence for PCV in the prevention of cases of vaccine serotype-specific invasive pneumococcal disease. The beneficial effects of PCVs in protecting individuals from a wide spectrum of pneumococcal diseases can be increased by improving the vaccine coverage and adhering to the recommended vaccination schedules. There is increasing evidence that PCV13 has reduced much of the post-PCV7 burden of pneumococcal diseases in the pediatric community, including reducing pneumococcal colonization and the incidence of invasive pneumococcal disease and mucosal diseases. This has also led to a reduction in antibiotic- resistant pneumococcal diseases. The role of PCV13 in clinical practice is evolving, with PCV13 now available for children and adolescents between the ages of 6 weeks and 17 years, thus ensuring that children in all age groups can be protected against vaccine-serotype pneumococcal diseases. Continued surveillance is warranted to monitor the impact of PCV13 on disease burden. Copyright © 2014 by Lippincott Williams & Wilkins.

Santamaria R.C.,University of Santiago de Compostela | Marino M.,University of Geneva | Putrov P.,University of Geneva
Journal of High Energy Physics | Year: 2011

We study various aspects of the matrix models calculating free energies and Wilson loop observables in supersymmetric Chern-Simons-matter theories on the threesphere. We first develop techniques to extract strong coupling results directly from the spectral curve describing the large N master field. We show that the strong coupling limit of the gauge theory corresponds to the so-called tropical limit of the spectral curve. In this limit, the curve degenerates to a planar graph, and matrix model calculations reduce to elementary line integrals along the graph. As an important physical application of these tropical techniques, we study N = 3 theories with fundamental matter, both in the quenched and in the unquenched regimes. We calculate the exact spectral curve in the Veneziano limit, and we evaluate the planar free energy and Wilson loop observables at strong coupling by using tropical geometry. The results are in agreement with the predictions of the AdS duals involving tri-Sasakian manifolds. © SISSA 2011.

Trigo-Mourino P.,University of Santiago de Compostela
Magnetic resonance in chemistry : MRC | Year: 2012

The dependence of molecular alignment with solvent nature and salt concentration has been investigated for mechanically stretched polyacrylamide copolymer gels. Residual dipolar couplings (RDCs) were recorded for D(2)O, DMSO-d(6), and DMSO-d(6)/D(2)O solutions containing different proportions of the solvents and different sodium chloride concentrations. Alignment tensors were determined by fitting the experimental RDCs to the DFT-computed structure of N-methylcodeinium ion. Analysis of the tensors shows that the degree of alignment decreases with the proportion of DMSO-d(6) as well as with the concentration of sodium chloride, most likely due to enhanced ion-pair aggregation. Furthermore, rotation of the alignment tensor is observed when increasing the salt concentration. Copyright © 2012 John Wiley & Sons, Ltd.

Carballo R.,University of Santiago de Compostela | Iglesias G.,University of Plymouth
Energy | Year: 2013

The objective of this work is to investigate the impact of a wave farm on the nearshore wave climate quantifying, for the first time, the interaction of the WECs (Wave Energy Converters) with the waves using ad hoc laboratory tests. To accomplish this objective, a procedure consisting of three main steps is implemented and illustrated with a case study: a wave farm of WaveCats (a lateral overtopping WEC) proposed for the Death Coast (NW Spain). First, the wave climate in the wave farm area is characterised and reference wave conditions are established. Second, wave-WEC interaction and, more specifically, wave energy transmission is determined by means of 3D physical model tests. Third, on the basis of the results of the laboratory tests, the impact of different layouts of the wave farm (single-row and two-row arrays) on the nearshore wave climate is computed using a high-resolution spectral wave model. The results indicate that the difference between the two layouts is negligible at a distance of 5000 m or greater past the farm. Although the case study concerns a specific WEC and area of deployment, the procedure is entirely general in that it can be applied to other WECs and areas of interest. © 2013 Elsevier Ltd.

Fernandez-Ramos A.,University of Santiago de Compostela
Angewandte Chemie - International Edition | Year: 2013

The correct interpretation is provided of how tunneling proceeds at low temperatures in the proton transfer Reactions (1) and (3) involving thiotropolone and tropolone (see the Arrhenius plots). It is also shown that the variational transition-state theory calculations carried out by Jose and Datta (Angew. Chem. 2012, 124, 9523; Angew. Chem. Int. Ed. 2012, 51, 9389), as well as their conclusions regarding these two processes are erroneous. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ramos V.,University of Santiago de Compostela | Iglesias G.,University of Plymouth
Energy Conversion and Management | Year: 2013

Due to the high cost of a tidal stream plant it is essential to select turbines that will have an optimum performance at the site in question. The objective of this work is twofold: (i) to present a procedure to compare the performance of different Tidal Stream Turbines (TSTs) at a given site, and (ii) to illustrate it by means of a case study. A new parameter, the site-specific turbine efficiency, is defined ad hoc and used alongside the availability and capacity factors, and the energy output over a reference period of time. These four performance parameters are determined for each turbine on the basis of the characteristics of the flow at the site. The procedure is illustrated with a case study in which two TSTs, the Gorlov Helicoidal Turbine and the Evopod, are compared for a site in an estuary. It is found that the availability and capacity factors of the Gorlov machine are higher (implying more operation hours and equivalent hours per annum) but the Evopod has larger site-specific efficiency and total energy output. In conclusion, a parametric approach that allows to compare the performance of different TSTs at any site of interest is presented and illustrated with a case study. © 2013 Elsevier Ltd. All rights reserved.

Veigas M.,University of Santiago de Compostela | Iglesias G.,University of Plymouth
Energy Conversion and Management | Year: 2013

The island of Tenerife, a UNESCO Biosphere Reserve in the Atlantic Ocean, aims to be energy self-sufficient in order to reduce its carbon footprint. To accomplish this goal it should develop the renewable sources, in particular wave and offshore wind energy. The objectives of this work are twofold; (i) to characterize the wave and offshore wind power distribution around the island and (ii) to determine which offshore area is best suited for their exploitation, taking into account the resource and other conditioning factors such as the bathymetry, distance to the coastline and ports, and offshore zoning. To carry out this research, hindcast wave and wind data obtained with numerical models are used alongside observations from meteorological stations. One area, in the vicinity of Puerto de la Cruz, is identified as having great potential for installing a hybrid floating wave-wind farm. Both resources are characterized for the area selected: the wave resource in terms of wave directions, significant wave heights and energy periods; the offshore wind resource in terms of directions and speeds in addition to the seasonality for the both resources. It is found that most of the wave resource is provided by N and NNW waves with significant wave heights between 1.5 m and 3.0 m and energy periods between 10 s and 14 s. It follows that the Wave Energy Converters deployed in the area should have maximum efficiency in those ranges. As for the offshore wind resource, most of the energy corresponds to NNE and NE winds with speeds between 9 and 14 m s-1, which should be taken into account when selecting the offshore wind turbines. © 2013 Elsevier Ltd. All rights reserved.

Vazquez A.,University of Santiago de Compostela | Iglesias G.,University of Plymouth
Ocean and Coastal Management | Year: 2015

The Choice Experiment (CE) technique is applied for the first time to one of the most promising marine renewables, tidal stream energy, with two objectives: (i) to investigate the public perceptions of this renewable, and (ii) to estimate the externalities, i.e., the monetary value of the impacts of a tidal stream farm. Both aspects, public perceptions and externalities, are relevant to the policy makers: if a policy is to maximise social welfare, it should be in line with public supporting attitudes and have positive externalities; moreover, the externalities are a prerequisite for establishing the appropriate level of subsidy (e.g., through a feed-in tariff). In this work the environmental and socioeconomic externalities are calculated independently, in a procedure that is illustrated through a case study: a prospective tidal farm in Ria de Ribadeo, an estuary in NW Spain. The public perceptions are found to be generally positive; notwithstanding, a certain degree of NIMBYism is detected. As regards the externalities, we find a positive net value. These findings are encouraging for the development of tidal stream energy, and the quantitative results provide a basis to establish the level of subsidisation. © 2014 Elsevier Ltd.

Gonzalez-Bello C.,University of Santiago de Compostela
Current Topics in Medicinal Chemistry | Year: 2016

The loss of effectiveness of current antibiotics caused by the development of drug resistance has become a severe threat to public health. Current widely used antibiotics are surprisingly targeted at a few bacterial functions - cell wall, DNA, RNA, and protein biosynthesis - and resistance to them is widespread and well identified. There is therefore great interest in the discovery of novel drugs and therapies to tackle antimicrobial resistance, in particular drugs that target other essential processes for bacterial survival. In the past few years a great deal of effort has been focused on the discovery of new inhibitors of the enzymes involved in the biosynthesis of aromatic amino acids, also known as the shikimic acid pathway, in which chorismic acid is synthesized. The latter compound is the synthetic precursor of L-Phe, L-Tyr, L-Phe, and other important aromatic metabolites. These enzymes are recognized as attractive targets for the development of new antibacterial agents because they are essential in important pathogenic bacteria, such as Mycobacterium tuberculosis and Helicobacter pylori, but do not have any counterpart in human cells. This review is focused on two key enzymes of this pathway, shikimate kinase and type II dehydroquinase. An overview of the use of structure-based design and computational studies for the discovery of selective inhibitors of these enzymes will be provided. A detailed view of the structural changes caused by these inhibitors in the catalytic arrangement of these enzymes, which are responsible for the inhibition of their activity, is described. © 2016 Bentham Science Publishers

Svenning J.-C.,University of Aarhus | Flojgaard C.,University of Aarhus | Baselga A.,University of Santiago de Compostela
Journal of Animal Ecology | Year: 2011

+Summary: 1.Environmental sorting, historical factors and neutral dynamics may all drive beta diversity (change in species composition across space), but their relative importance remains unresolved. In the case of European mammals, key potential drivers of large-scale beta diversity include current climate, neutral dynamics and two historical factors: Pleistocene glaciations and peninsular dynamics (immigration from extra-regional eastern faunal source areas and inter-linked relictual survival and evolutionary differentiation in isolated areas). 2.We assessed the relative importance of these drivers using a novel analytical framework to deconstruct beta diversity of non-volant mammals in Europe (138 species) into its turnover (change in species composition because of species replacements) and nestedness components (change in species composition because of species richness differences) at continental and regional (250000km2) scales. 3.We found continental-scale mammal beta diversity to be mainly caused by spatial turnover (99·9%), with only a small contribution (0·1%) from nestedness. 4.Current climate emerged as an important driver of beta diversity, given the strong continental-scale turnover, particularly in north-south direction, i.e., in line with the latitudinal climate gradient, and, more directly, the strong correlation of climate with spatial turnover at both continental and regional scales. 5.However, there was also evidence for the importance of non-climatic drivers. Notably, the compositional variation purely accounted for by space was greater than that purely accounted for by environment for both the turnover and the nestedness component of beta diversity. Furthermore, the strong longitudinal turnover within Southern Europe is in accordance with the region's long-term climatic stability having allowed multiple refugia and local evolutionary diversification. As expected from peninsular dynamics, there was increasing dissimilarity with geographic distance in an east-west direction because of nestedness, but only in Central and Northern Europe. 6.In conclusion, European mammal beta diversity mainly reflects spatial turnover and only to a limited extent nestedness and is driven by current climate in combination with historical - and perhaps, neutral - dynamics. These findings suggest that a key challenge for climate-change predictive studies will be taking the influence of non-climatic factors into account. © 2010 The Authors. Journal compilation © 2010 British Ecological Society.

Sobarzo-Sanchez E.,University of Santiago de Compostela
PloS one | Year: 2013

Leishmaniasis is a growing health problem worldwide. As there are certain drawbacks with the drugs currently used to treat human leishmaniasis and resistance to these drugs is emerging, there is a need to develop novel antileishmanial compounds, among which isoquinoline alkaloids are promising candidates. In this study, 18 novel oxoisoaporphine derivatives were synthesized and their possible antileishmanial activity was evaluated. The in vitro activity of these derivatives against Leishmania amazonensis axenic amastigotes was first evaluated, and the selected compounds were then tested in an inhibition assay with promastigotes of L. infantum, L. braziliensis, L. amazonensis and L. guyanensis, and with intracellular amastigotes of L. infantum and L. amazonensis. Finally, the most active compounds, OXO 1 (2,3-dihydro-7H-dibenzo[de,h]quinolin-7-one) and OXO 13 (2,3,8,9,10,11-hexahydro-7H-dibenzo[de,h]quinolin-7-one), were tested in BALB/c mice infected with L. infantum. Treatment of mice at a dose of 10 mg/kg with OXO 1 yielded significant reductions (p<0.05) in parasite burden in liver and spleen (99% and 78%, respectively) whereas with OXO 13 were not significant. Although previous reports suggest that this family of molecules displays inhibitory activity against monoamine oxidase A and acetylcholinesterase, these enzymes were not confirmed as targets for antileishmanial activity on the basis of the present results. However, after development of a new bioinformatics model to analyze the Leishmania proteome, we were able to identify other putative targets for these molecules. The most promising candidates were four proteins: two putative pteridine reductase 2 (1MXF and 1MXH), one N-myristoyltransferase (2WUU) and one type I topoisomerase (2B9S).

Monteiro S.M.S.,Polytechnic Institute of Cavado and Ave | Aibar-Guzman B.,University of Santiago de Compostela
Corporate Social Responsibility and Environmental Management | Year: 2010

Similarly to what has happened in other countries, since the early 1990s Portuguese companies have developed corporate environmental reporting practices in response to internal and external factors. This paper is based on empirical research directed to both the study of environmental reporting practices developed by Portuguese companies and the identification of the factors that explain the extent to which these companies disclose environmental information. This study focuses on the environmental disclosures made in the annual reports by a sample of 109 large firms operating in Portugal during the period 2002-04. Using the content analysis technique we have developed an index in order to assess the presence of the environmental disclosures in companies' annual reports and their breadth. Based on the extant literature, several characteristics relating to firms' attributes were selected and their influence on the level of environmental disclosure was tested empirically. The selected explanatory variables were firm size, industry membership, profitability, foreign ownership, quotation on the stock market and environmental certification. The results reveal that, in spite of the fact that the level of environmental information disclosed during the period 2002-04 is low, the extent of environmental disclosure has increased as well as the number of Portuguese companies that disclose environmental information. Moreover, the firm size and the fact that a company is listed on the stock market are positively related to the extent of environmental disclosure. This study adds to the international research on environmental disclosure by providing empirical data from a country, Portugal, where empirical evidence is still relatively unknown, extending the scope of the current understanding of the environmental reporting practices. © 2009 John Wiley & Sons, Ltd and ERP Environment.

Orosa B.,Complexo Hospitalario Universitario Of Santiago Of Compostela | Gonzalez A.,Complexo Hospitalario Universitario Of Santiago Of Compostela | Mera A.,Complexo Hospitalario Universitario Of Santiago Of Compostela | Gomez-Reino J.J.,University of Santiago de Compostela | Conde C.,Complexo Hospitalario Universitario Of Santiago Of Compostela
Arthritis and Rheumatism | Year: 2012

Objective To investigate the role of lysophosphatidic acid (LPA) receptors in the proliferation and apoptosis of fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis (RA). Methods Expression of LPA receptors 1-3 was analyzed by real-time polymerase chain reaction (PCR). LPAR1 and LPAR2 were suppressed in RA FLS by small interfering RNA (siRNA) transfection. Proliferation of RA FLS after tumor necrosis factor (TNF) and LPA stimulation was determined with a luminescent cell viability assay. Apoptosis was analyzed by quantification of nucleosome release and measurement of activated caspase 3/7. Genes involved in the apoptotic response were identified with a human apoptosis PCR array and validated with Western blot assays. The requirement of these genes for apoptosis sensitization was assessed by siRNA transfection. Secretion of mediators of inflammation was analyzed by enzyme-linked immunosorbent assay. Results Only LPAR1 and LPAR2 were expressed by RA FLS, and their levels were higher than those in osteoarthritis (OA) FLS. Suppression of LPAR1 abrogated TNF-induced proliferation and sensitized the RA FLS, but not the OA FLS, to TNF-induced apoptosis. These changes occurred despite an increased early inflammatory response to TNF. Sensitization to apoptosis was associated with changes in expression of multiple apoptosis-related genes. Three of the up-regulated proapoptotic genes were further studied to confirm their involvement. In contrast, suppression of LPAR2 showed no effect in any of these analyses. Conclusion LPA1 is an important receptor in RA FLS. Its suppression is accompanied by a global increase in the response to TNF that is ultimately dominated by sensitization to apoptosis. Copyright © 2012 by the American College of Rheumatology.

Bautista I.,University of Lisbon | Bautista I.,University of Santiago de Compostela | Dias de Deus J.,University of Lisbon
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

We test the validity of the black disk limit in elastic scattering by studying the evolution of the dip in the scaling variable τ=-tDσtot, where tD is the transverse momentum squared at the dip and σtot the total cross section. As s→∞ and -tD→0, τ may consistently be approaching the black disc value, τ→s→∞τBD=35.92 GeV2mb. © 2012 Elsevier B.V.

Rodriguez G.,University of Santiago de Compostela
Proceedings of the 32nd International Cosmic Ray Conference, ICRC 2011 | Year: 2011

The properties of extensive air showers (EAS) induced by cosmic rays with zenith angles up to 80° can be measured accurately in the surface detector (SD) of the Pierre Auger Observatory. Using a model of the density pattern of muons, extracted from simulations, the shower size, N19, related to the total number of muons in EAS, is estimated from the signals measured in the SD stations. The accuracy of the reconstruction of N19 is tested using a large sample of simulated events. The shower size is calibrated using the shower energy measured with the fluorescence detector (FD) in a sub-sample of high-quality hybrid events (i.e. events detected simultaneously by SD and FD). This allows the number of muons versus energy to be measured. We compare the number of muons versus energy as obtained through simulations with that measured in data. We find that none of the current shower models, neither for proton nor for iron primaries, are able to predict as many muons as are observed.

Aragon P.,Complutense University of Madrid | Baselga A.,University of Santiago de Compostela | Lobo J.M.,CSIC - National Museum of Natural Sciences
Journal of Applied Ecology | Year: 2010

1. Biological invasions represent a major threat to human health, ecosystem functioning and global biodiversity. Insect pests affecting agriculture and forestry are of special importance. Estimations of climatic similarity between a species' native range and potential zones of invasion can be useful for preventing new invasions, spreads and ulterior contacts among populations from multiple invasions.2. We estimated areas climatically favourable for the establishment of the western corn rootworm (WCR), an insect pest of maize Zea mays in North America that has recently invaded Central Europe through multiple invasions, and it has the potential of invasion mainly in the Northern Hemisphere.3. We used complementary techniques to assess the biological relevance of predictors and obtain areas of climatic favourability. The biological relevance of variables was first assessed accounting for two main components of the WCR's environmental niche (marginality and specialisation). Then, the most relevant predictors were used to obtain either climatic envelopes or environmental distances regarding the WCR's native range. Model outputs and predictor relevance were independently assessed in the currently invaded region of Europe and through the spatial projection of proposed physiological thresholds from previous empirical studies. Lastly, as examples of application for given time periods, we fed back results of environmental distances with maize data for a 10-year period in Europe, and refined global risk maps with the main maize zones for the year 2000.4. We present global zones of climatic favourability and invasion risk for the WCR, with emphasis on the Northern Hemisphere. The northern and north-west range limits predicted by the climatic envelope in the WCR's native range mirrored the independently characterised physiological limits. Also, our model outputs explained some of the patterns observed in Europe supporting the validity of our procedures.5. Synthesis and applications. Assessments of climatic favourability for the western corn rootworm can provide information on areas of invasion risk. Our study highlights the combination of holistic and reductionist approaches as a useful protocol to evaluate models and/or infer causality. Our methodology can be an efficient tool in combating future potential invasions, spreads and secondary contact zones of insect pests by reducing uncertainty regarding where to allocate prevention and/or eradication efforts. © 2010 The Authors. Journal compilation © 2010 British Ecological Society.

Marquet C.,University of Santiago de Compostela | Marquet C.,CERN
Nuclear Physics A | Year: 2013

I present the state of our understanding of the QCD dynamics at play in the parton saturation regime of nuclear wave functions. I explain what are the biggest open questions in the field, their intrinsic interest, but also why is it important to answer them from the quark-gluon-plasma physicists' perspective. Focusing on those aspects that proton-nucleus collisions cannot investigate to a satisfactory degree, I show that future high-energy electron-ion colliders have the potential to address these questions, providing thorough answers in most cases, and exploratory measurements otherwise. © 2013 Elsevier B.V.

Pardo V.,University of California at Davis | Pardo V.,University of Santiago de Compostela | Pickett W.E.,University of California at Davis
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

The (SrTiO3) m / (SrVO3) n d0 - d1 multilayer system is studied with first-principles methods through the observed insulator-to-metal transition with increasing thickness of the SrVO3 layer. When correlation effects with reasonable magnitude are included, crystal-field splittings from the structural relaxations together with spin-orbit coupling (SOC) determines the behavior of the electronic and magnetic structures. These confined slabs of SrVO3 prefer Qorb = (π,π) orbital ordering of ℓz =0 and ℓz =-1 (jz =- 1/2) orbitals within the plane, accompanied by Qspin = (0,0) spin order (ferromagnetic alignment). The result is a SOC-driven ferromagnetic Mott insulator. The orbital moment of 0.75 μB strongly compensates the spin moment on the ℓz =-1 sublattice. The insulator-metal transition for n=1→5 (occurring between n=4 and n=5) is reproduced. Unlike in the isoelectronic d0 - d 1 TiO2 / VO2 (rutile structure) system and in spite of some similarities in orbital ordering, no semi-Dirac point is encountered but the insulator-to-metal transition occurs through a different type of unusual phase. For n=5 this system is very near (or at) a unique semimetallic state in which the Fermi energy is topologically determined and the Fermi surface consists of identical electron and hole Fermi circles centered at k=0. The dispersion consists of what can be regarded as a continuum of radially directed Dirac points, forming a "Dirac circle." © 2010 The American Physical Society.

Iglesias G.,University of Santiago de Compostela | Diz-Lois G.,Ports of Galicia | Pinto F.T.,University of Porto
Coastal Engineering | Year: 2010

Headland-bay beaches are a typical feature of many of the world's coastlines. Their curved planform has aroused much interest since the early days of Coastal Engineering. Modelling this characteristic planform is a task of great interest, not least in relation to projects of coastal structures whose effects on the shoreline must be studied from the planning stages. In this work, Artificial Intelligence is applied to this task-in particular, artificial neural networks (ANNs). Unlike conventional planform models, they are not based on a given mathematical expression of the shoreline curve. Instead, they learn from experience (from a number of training cases) how the planform of a headland-bay beach is shaped, with due regard to the obliquity of incident waves. Three artificial neural networks, with different input/output structures, are implemented and subsequently trained with a number of bays. Once trained, they are tested for validation on other headland-bay beaches. Finally, the most performing neural network is compared with a state-of-the-art planform model. © 2009.

Perez-Munuzuri V.,Meteogalicia | Huhn F.,University of Santiago de Compostela
Nonlinear Processes in Geophysics | Year: 2010

Horizontal mixing has been found to play a crucial role in the development of spatial plankton structures in the ocean. We study the influence of time and length scales of two different horizontal two-dimensional (2-D) flows on the growth of a single phytoplankton patch. To that end, we use a coupled model consisting of a standard three component ecological NPZ model and a flow model able to mimic the mesoscale structures observed in the ocean. Two hydrodynamic flow models are used: a flow based on Gaussian correlated noise, for which the Eulerian length and time scales can be easily controlled, and a multiscale velocity field derived from altimetry data in the North Atlantic ocean. We find the optimal time and length scales for the Gaussian flow model favouring the plankton spread. These results are used for an analysis of a more realistic altimetry flow. We discuss the findings in terms of the time scale of the NPZ model, the qualitative interaction of the flow with the reaction front and a Finite-Time Lyapunov Exponent analysis.

Beuf G.,Brookhaven National Laboratory | Beuf G.,University of Santiago de Compostela
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

The NLO generalization of the dipole factorization formula for the structure functions F 2 and F L at low x is calculated using light-front perturbation theory. That result gives some interesting insight into the kinematics of initial state parton showers in mixed-space. © 2012 American Physical Society.

Pardo V.,University of California at Davis | Pardo V.,University of Santiago de Compostela | Pickett W.E.,University of California at Davis
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

Multilayer (TiO2)m / (VO2)n nanostructures (d1 - d0 interfaces with no polar discontinuity) show a metal-insulator transition with respect to the VO 2 layer thickness in first-principles calculations. For n≥5 layers, the system becomes metallic, while being insulating for n=1 and 2. The metal-insulator transition occurs through a semi-Dirac point phase for n=3 and 4, in which the Fermi surface is pointlike and the electrons behave as massless along the zone diagonal in k space and as massive fermions along the perpendicular direction. We provide an analysis of the evolution of the electronic structure through this unprecedented insulator-to-metal transition, and identify it as resulting from quantum confinement producing a nonintuitive orbital ordering on the V d1 ions, rather than being a specific oxide interface effect. Spin-orbit coupling does not destroy the semi-Dirac point for the calculated ground state, where the spins are aligned along the rutile c axis, but it does open a substantial gap if the spins lie in the basal plane. © 2010 The American Physical Society.

Salgado C.A.,University of Santiago de Compostela | Salgado C.A.,CERN
Nuclear Physics A | Year: 2013

I provide a summary of the theoretical talks in Hard Probes 2012 together with some personal thoughts about the present and the future of the field. © 2012 Elsevier B.V.

Phillips C.,University of Santiago de Compostela
Forensic Science International: Genetics | Year: 2014

Using the Thomson Reuters' Web of Knowledge bibliometric tool enables the analysis of citation patterns for the articles published in FSI: Genetics since it was launched. This brief survey identifies the most cited articles published by the journal since its inception and amongst these, the most impactful original research articles: those showing the highest citation rates per year since their publication. © 2014 Elsevier Ireland Ltd.

Campo-Cacharron A.,Facultade de Ciencias | Cabaleiro-Lago E.M.,Facultade de Ciencias | Rodriguez-Otero J.,University of Santiago de Compostela
ChemPhysChem | Year: 2012

The characteristics of the interaction of anions with naphthalendiimides, the basic structural motif of a newly synthesized anion channel based on aniona⋯π interactions, are studied by computational methods. Stable complexes are formed with bromide, chloride, fluoride or hydroxide anions, which exhibit strong aniona⋯π interactions in the gas phase. Following the sequence of the polarizing power of the anions, hydroxide and fluoride complexes are the most strongly interacting. The presence of a small number of water molecules strongly affects the aniona⋯π interactions, especially for hydroxide and fluoride complexes, so the differences in interaction strength among the anions drop significantly. The calculations suggest that a small number of water molecules can be crucial to reducing dehydration cost and contributing to stabilizing interactions with the naphthalendiimide units. Water power: DFT calculations show that naphthalendiimides establish strong aniona⋯π interactions in the gas phase (see picture). The presence of a small number of water molecules significantly alters the aniona⋯π interaction, thereby suggesting its crucial role in overcoming dehydration costs. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Buntner D.,University of Santiago de Compostela | Spanjers H.,Technical University of Delft | van Lier J.B.,Technical University of Delft
Water Research | Year: 2014

The objective of the present study was to evaluate the impact of excess aerobic sludge on the specific methanogenic activity (SMA), in order to establish the maximum allowable aerobic sludge loading. In batch tests, different ratios of aerobic sludge to anaerobic inoculum were used, i.e. 0.03, 0.05, 0.10 and 0.15, showing that low ratios led to an increased SMA. However, the ratio 0.15 caused more than 20% SMA decrease. In addition to the SMA tests, the potential influence of biopolymers and extracellular substances, that are generated as a result of excess aerobic sludge hydrolysis, on membrane performance was determined by assessing the fouling potential of the liquid broth, taking into account parameters such as specific resistance to filtration (SRF) and supernatant filterability (SF). Addition of aerobic sludge to the anaerobic biomass resulted in a high membrane fouling potential. The increase in biopolymers could be ascribed to aerobic sludge hydrolysis. A clear positive correlation between the concentration of the colloidal fraction of biopolymer clusters (cBPC) and the SRF was observed and a negative correlation between the cBPC and the SF measured at the end of the above described SMA tests. The latter implies that sludge filtration resistance increases when more aerobic sludge is hydrolyzed, and thus more cBPC is released. During AnMBR operation, proteins significantly contributed to sludge filterability decrease expressed as SRF and SF, whereas the carbohydrate fraction of SMP was of less importance due to low concentrations. On the contrary, carbohydrates seemed to improve filterability and diminish SRF of the sludge. Albeit, cBPC increase caused an increase in mean TMP during the AnMBR operation, confirming that cBPC is positively correlated to membrane fouling. © 2013 Elsevier Ltd.

Dominguez-Munoz J.,University of Santiago de Compostela
Advances in Medical Sciences | Year: 2011

Pancreatic exocrine insufficiency with steatorrhea is a major consequence of pancreatic diseases (e.g. chronic pancreatitis, cystic fibrosis, severe acute necrotizing pancreatitis, pancreatic cancer), extrapancreatic diseases like celiac disease and Crohn's disease, and gastrointestinal and pancreatic surgical resections. Recognition of this entity is highly relevant to avoid malnutrition-related morbidity and mortality. Therapy of pancreatic exocrine insufficiency is based on the oral administration of pancreatic enzymes aiming at providing the duodenal lumen with sufficient amount of active lipase at the time of gastric emptying of nutrients. Administration of enzymes in form of enteric-coated minimicrospheres avoids acid-mediated lipase inactivation and ensures gastric emptying of enzymes in parallel with nutrients. Despite that, factors like an acidic intestinal pH and bacterial overgrowth may prevent normalization of fat digestion even in compliant patients. The present article critically reviews current therapeutic approaches to pancreatic exocrine insufficiency. © Medical University of Bialystok, Poland.

Marazuela M.,Autonomous University of Madrid | Ramos-Levi A.,Autonomous University of Madrid | Sampedro-Nunez M.,Autonomous University of Madrid | Bernabeu I.,University of Santiago de Compostela
Endocrine | Year: 2014

Cabergoline is an ergot-derived dopamine D2 receptor agonist which may be effective for the medical management of acromegaly. Its efficacy in reducing growth hormone and IGF-I levels, as well as its antiproliferative and pro-apoptotic effects on pituitary tumor cells, has been observed in several studies. Cabergoline may be used alone or as an add-on therapy to patients who are partially resistant to somatostatin analogs (SSA), or who do not achieve complete control with maximum doses of pegvisomant (PEG). Additionally, the convenience of its oral administration, allowing better compliance, and its lower economic cost, in comparison with SSA and PEG, favor cabergoline as an attractive option for acromegalic patients, who frequently require long-life medical treatment to achieve disease control. The few adverse events observed with prolonged DA therapy, mainly regarding cardiac valve disease, are not frequent at the doses generally used in acromegaly. © 2014 Springer Science+Business Media.

Baselga A.,University of Santiago de Compostela
Methods in Ecology and Evolution | Year: 2013

Summary: Dissimilarity measures can be formulated using matching components that can be defined as the intersection in terms of species composition of both sets (a) and the relative complements of each set (b and c respectively). Previous work has extended these matching components to abundance-based measures of dissimilarity. Using these matching components in terms of species abundances I provide a novel partition separating two components of abundance-based dissimilarity: (i) balanced variation in abundance, whereby the individuals of some species in one site are substituted by the same number of individuals of different species in another site; and (ii) abundance gradients, whereby some individuals are lost from one site to the other. New indices deriving from the additive partition of Bray-Curtis dissimilarity are presented, each one accounting separately for these two antithetic components of assemblage variation. An example comparing the patterns of increase of assemblage dissimilarity with spatial distance in two tropical forests is provided to illustrate the usefulness of the novel partition to discern the different sources of assemblage variation. The widely used Bray-Curtis index of dissimilarity is the result of summing these two sources of dissimilarity, and therefore might consider equivalent patterns that are markedly different. Therefore, the novel partition may be useful to assess biodiversity patterns and to explore their causes, as substitution and loss of individuals are patterns that can derive from completely different processes. © 2013 British Ecological Society.

Vuorinen A.,Helsinki Institute of Physics | Zhu Y.,University of Santiago de Compostela
Journal of High Energy Physics | Year: 2015

Abstract: We revisit the determination of the two-loop spectral function in the shear channel of hot Yang-Mills theory. Correcting a technical error in an earlier computation is seen to improve the infrared behavior of the quantity significantly, while a partial Hard Thermal Loop resummation is seen to have only a very minor numerical effect on the result. These facts make it possible to straightforwardly apply the spectral function to the corresponding imaginary time correlator and the shear sum rule. © 2015, The Author(s).

Stankova T.V.,Bulgarian Academy of Science | Dieguez-Aranda U.,University of Santiago de Compostela
Annals of Forest Research | Year: 2013

The height-diameter relationship is an important and extensively investigated forest model, but generalized and mixed-effects models of wider applicability are currently lacking in the forest modeling literature for Scots pine (Pinus sylvestris L.) plantations in Bulgaria. Considering the practical advantages of deterministic and mixed-effects models, the present study aims to derive a generalized deterministic height-diameter relationship and a simple mixed-effects model for plantation-grown Scots pine in Bulgaria. Ten generalized and six local models of adequate mathematical properties were selected and examined in several subsequent steps with a representative data set. A deterministic model was derived for tree height reconstruction from the individual tree diameters, stand dominant height and diameter, number of trees per hectare and stand age. Mixed-effects models were developed from the individual-tree and stand diameters and heights applicable to determine the height-diameter relationship in field surveys. Both types of models can be applied with confidence, according to their advantages and specifications, for estimating the height-diameter relationship of Scots pine plantations in Bulgaria, presenting a unique contribution for the particular species, study area and type of model. The choice of the tested models is relevant to the height-diameter relationship investigation of biologically related and geographically close species and types of stands and the study procedure allows repetition of the work to provide reliable solutions of the problem where information on such type of model is deficient or incomplete.

Kimura Y.,University of Oviedo | Lin H.,University of Santiago de Compostela
Journal of High Energy Physics | Year: 2012

We study the 1/4 BPS geometries corresponding to the 1/4 BPS operators of the dual gauge theory side, in N = 4 SYM. By analyzing asymptotic structure and flux integration of the geometries, we present a mapping between droplet configurations arising from the geometries and Young diagrams of the Brauer algebra. In particular, the integer k classifying the operators in the Brauer basis is mapped to the mixing between the two angular directions. © SISSA 2012.

Rodicio M.C.,University of Santiago de Compostela | Barreiro-Iglesias A.,University of Edinburgh
Revista de Neurologia | Year: 2012

Spinal cord injuries are an important sanitary and economical problem for the society. In mammals, including humans, a traumatic injury to the spinal cord leads to a loss of motor and sensorial function, which is irreversible due to the low regenerative ability of the central nervous system. In contrast to mammals, functional recovery occurs spontaneously after a complete spinal cord transection in lampreys. Functional recovery occurs because in these animals about 50% of the reticulospinal axons regenerate after injury and also because of the occurrence of processes of reorganization and plasticity of the spinal circuits. In this review, we first analyze the characteristics and regeneration ability of lampreys as compared to mammals. Then, we compile the knowledge about the process of recovery after a spinal cord injury acquired in studies using the lampreys as animal model and finally we provide some general perspectives about the molecular processes implicated in regeneration that can be investigated in a very advantageous way in this animal model and which knowledge could allow to develop new therapies for patients suffering spinal cord injury.

Hoare B.,Imperial College London | J. Hollowood T.,University of Swansea | Miramontes J.L.,University of Santiago de Compostela
Journal of High Energy Physics | Year: 2012

A set of four factorizable non-relativistic S-matrices for a multiplet of fundamental particles are defined based on the R-matrix of the quantum group deformation of the centrally extended superalgebra su(2j2). The S-matrices are a function of two independent couplings g and q = e iπ=k. The main result is to find the scalar factor, or dressing phase, which ensures that the unitarity and crossing equations are satisfied. For generic (g; k), the S-matrices are branched functions on a product of rapidity tori. In the limit k → ∞, one of them is identified with the S-matrix describing the magnon excitations on the string world sheet in AdS 5×S 5, while another is the mirror S-matrix that is needed for the TBA. In the g → ∞ limit, the rapidity torus degenerates, the branch points disappear and the S-matrices become meromorphic functions, as required by relativistic S-matrix theory. However, it is only the mirror S-matrix which satisfies the correct relativistic crossing equation. The mirror S-matrix in the relativistic limit is then closely related to that of the semi-symmetric space sine-Gordon theory obtained from the string theory by the Pohlmeyer reduction, but has anti-symmetric rather than symmetric bound states. The interpolating S-matrix realizes at the quantum level the fact that at the classical level the two theories correspond to difierent limits of a one-parameter family of symplectic structures of the same integrable system. © SISSA 2012.

Sun N.,University of Alabama | Rodriguez H.,University of Santiago de Compostela | Rahman M.,University of Alabama | Rogers R.D.,University of Alabama
Chemical Communications | Year: 2011

Certain ionic liquids have been shown to dissolve cellulose, other biopolymers, and even raw biomass under relatively mild conditions. This particular ability of some ionic liquids, accompanied by a series of concurrent advantages, enables the development of improved processing strategies for the manufacturing of a plethora of biopolymer-based advanced materials. The more recent discoveries of dissolution of lignocellulosic materials (e.g., wood) in ionic liquids, with at least partial separation of the major constituent biopolymers, suggest further paths towards the achievement of a truly sustainable chemical and energy economy based on the concept of a biorefinery which provides chemicals, materials, and energy. Nonetheless, questions remain about the use of ionic liquids and the advisability of introducing any new process which utilizes bulk synthetic chemicals which have to be made, disposed of, and prevented from entering the environment. In this article, we discuss our own journey from the discovery of the dissolution of cellulose in ionic liquids to the cusp of an enabling technology for a true biorefinery and consider some of the key questions which remain. © 2011 The Royal Society of Chemistry.

Perez-Munuzuri V.,University of Santiago de Compostela | Huhn F.,ETH Zurich
Nonlinear Processes in Geophysics | Year: 2013

Spatial maps of the finite-time Lyapunov exponent (FTLE) have been used extensively to study LCS in two-dimensional dynamical systems, in particular with application to transport in unsteady fluid flows. We use the time-periodic double-gyre model to compare spatial fields of FTLE and the path-integrated Eulerian Okubo-Weiss parameter (OW). Both fields correlate strongly, and by solving the dynamics of the deformation gradient tensor, a theoretical relationship between both magnitudes has been obtained. While for long integration times more and more FTLE ridges appear that do not seem to coincide with the stable manifold, ridges in the field of path-integrated OW represent fewer additional structures.©Author(s) 2013.

Le Rouzic A.,French National Center for Scientific Research | Alvarez-Castro J.M.,University of Santiago de Compostela | Hansen T.F.,University of Oslo
Evolutionary Biology | Year: 2013

Using a multilinear model of epistasis we explore the evolution of canalization (reduced mutational effects) and evolvability (levels of additive genetic variance) under different forms of stabilizing and fluctuating selection. We show that the total selection acting on an allele can be divided into a component deriving from adaptation of the trait mean, a component of canalizing selection favoring alleles that epistatically reduce the effects of other allele substitutions, and a component of conservative selection disfavoring rare alleles. While canalizing selection operates in both stable and fluctuating environments, it may not typically maximize canalization, because it gets less efficient with increasing canalization, and reaches a balance with drift, mutation and indirect selection. Fluctuating selection leads to less canalized equilibria than stabilizing selection of comparable strength, because canalization then becomes influenced by erratic correlated responses to shifting trait adaptation. We conclude that epistatic systems under bounded fluctuating selection will become less canalized than under stabilizing selection and may support moderately increased evolvability if the amplitude of fluctuations is large, but canalization is still stronger and evolvability lower than expected under neutral evolution or under patterns of selection that shift the trait in directions of positive (reinforcing) epistasis. © 2013 Springer Science+Business Media New York.

Ramos V.,University of Santiago de Compostela | Ringwood J.V.,National University of Ireland
Energy | Year: 2016

For wave energy to become a commercially viable source of energy, a complete understanding of the wave resource characterisation is needed. In this context, the IEC (International Electrotechnical Commission) has developed a technical specification for the assessment of the wave resource, IEC-TS 62600-101: Marine energy-Wave, tidal and other water current converters-Part 101: Wave energy resource assessment and characterisation (IEC-62600-101), which presents a series of recommendations for standardising wave resource characterisation. The IEC-62600-101 classifies resource assessment studies into three different classes: reconnaissance, feasibility and design. The model setup requirements (mesh resolution, boundary conditions) and the effort (validation process, computational times) vary considerably from one class to the other. On these grounds, the objective of this work is to explore this methodology using the Irish West Coast as a case study. Overall, it was found that the methodology proposed performs well, offering a detailed characterisation of the resource; however, with the aim of making the technical specification more manageable, some aspects related to the seasonality of the wave resource and the validation and model setup procedures may be revisited for future editions. © 2016 Elsevier Ltd.

Rodriguez-Aros A.D.,University of La Coruna | Viano J.M.,University of Santiago de Compostela
Zeitschrift fur Angewandte Mathematik und Physik | Year: 2012

The authors derive and justify two models for the bending-stretching of a viscoelastic rod by using the asymptotic expansion method. The material behaviour is modelled by using a general Kelvin-Voigt constitutive law. © 2011 Springer Basel AG.

Kurkela A.,CERN | Kurkela A.,University of Stavanger | Zhu Y.,University of Santiago de Compostela
Physical Review Letters | Year: 2015

We numerically solve the (2+1)-dimensional effective kinetic theory of weak coupling QCD under longitudinal expansion, relevant for early stages of heavy-ion collisions. We find agreement with viscous hydrodynamics and classical Yang-Mills simulations in the regimes where they are applicable. By choosing initial conditions that are motivated by a color-glass-condensate framework, we find that for Qs=2 GeV and αs=0.3 the system is approximately described by viscous hydrodynamics well before τ 1.0 fm/c. © 2015 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "http://creativecommons.org/licenses/by/3.0/" Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Lopez M.,University of Santiago de Compostela | Iglesias G.,University of Plymouth | Kobayashi N.,University of Delaware
Applied Ocean Research | Year: 2012

A new container terminal will soon be inaugurated in the Port of Ferrol (Spain). Sea level observations show the occurrence of seiche events in the basin. The objective of this work is to investigate the long wave oscillations and their dependence on the tidal level. Two analysis techniques, fast Fourier transform (FFT) and short time Fourier transform (STFT), are applied. Time-averaged spectra corresponding to different tidal levels are obtained with the FFT, whereas seiche events are identified on spectrograms computed with the STFT. The time-averaged power density spectra features eleven well-marked peaks, with moderate to high amplification. A clear influence of the tide on the spectral peaks is found, with most peaks presenting higher frequencies and greater power densities at high tide. The analysis of the individual seiche events shows that the behavior of long wave energy in the basin varies across the spectrum; on these grounds, three frequency bands are proposed: LF (low frequency), VLF (very low frequency), and ULF (ultra low frequency). The LF band exhibits a high correlation with the offshore swell energy, both outside and inside the harbor. At the other end of the long wave spectrum, the ULF band is only weakly correlated with the swell; it responds to a different forcing, possibly related to atmospheric disturbances. Finally, the intermediate VLF band presents a mixed character, with influences both from the swell and the other driving agent. The contributions of the paper are as follows. First, the long wave behavior at the Port of Ferrol, a major port in Spain, is characterized for the first time. Second, two contrasting behaviors affecting different frequency ranges are identified-one is proven to be swell-driven, whereas the other is proven, on the contrary, to not be swell-related. And, finally, the tidal oscillation is found to be relevant to the long wave behavior within the port, for it affects both the frequencies and power densities of the spectral peaks-but not to the generation of long waves outside the harbor. © 2012 Elsevier Ltd.

Fernandez E.F.,University of Jaen | Siefer G.,Fraunhofer Institute for Solar Energy Systems | Almonacid F.,University of Jaen | Loureiro A.J.G.,University of Santiago de Compostela | Perez-Higueras P.,University of Jaen
Solar Energy | Year: 2013

While single junction solar cells are mainly influenced by changes in irradiance and temperature, multi junction concentrator solar cells show complex behaviour as their performance is also strongly influenced by changes in spectrum. Despite this, when studying the system, it is possible to reduce the problem to a set of parameters that could easily be measured and fitted. A simple model to obtain the maximum power point of multi junction solar cells under temperature and spectral changes is proposed. This model is based on a single diode model and is described by a simple set of equations that are easy to fit within a computational program. The model could be useful to understand the behaviour of multi junction solar cells and also CPV technology under real conditions. The main purpose of this paper is to define a simple way to estimate the maximum power point of a multi junction solar cell under spectral and temperature changes at one sun conditions. © 2013 Elsevier Ltd.

Yushkov A.,University of Santiago de Compostela
EPJ Web of Conferences | Year: 2013

Several methods for estimating the muonic part of the signal observed in the surface Cherenkov detectors have been developed within the Pierre Auger Collaboration in the recent years. The muon shower content, derived from data with these methods, is found to be significantly larger in comparison with predictions of QGSJET II interaction model. © Owned by the authors, published by EDP Sciences, 2013.

Matias J.M.,University of Vigo | Reboredo J.C.,University of Santiago de Compostela
Journal of Forecasting | Year: 2012

We studied the predictability of intraday stock market returns using both linear and nonlinear time series models. For the S&P 500 index we compared simple autoregressive and random walk linear models with a range of nonlinear models, including smooth transition, Markov switching, artificial neural network, nonparametric kernel regression and support vector machine models for horizons of 5, 10, 20, 30 and 60 minutes. The empirical results indicate that nonlinear models outperformed linear models on the basis of both statistical and economic criteria. Specifically, although return serial correlation receded by around 10 minutes, return predictability still persisted for up to 60 minutes according to nonlinear models, even though profitability decreases as time elapses. More flexible nonlinear models such as support vector machines and artificial neural network did not clearly outperform other nonlinear models. Copyright © 2011 John Wiley & Sons, Ltd.

Diz Dios P.,University of Santiago de Compostela | Scully C.,University College London
Oral Diseases | Year: 2014

This study summarizes the adverse effects of antiretroviral therapy (ART) agents against HIV on orofacial health and health care. Current antiretroviral agents fall mainly into three major classes: nucleoside reverse-transcriptase inhibitors (NRTIs), non-nucleoside reverse-transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs) - now with the new classes of fusion inhibitors, entry inhibitors -CCR5 co-receptor antagonists and HIV integrase strand transfer inhibitors. Many of the ART agents can have adverse orofacial effects, or can give rise to allergies or drug interactions - the optimum anti-HIV drug has yet to be found. There are few orofacial adverse effects that characterize a particular ART class, but erythema multiforme (EM), ulcers and xerostomia may be associated with reverse-transcriptase inhibitors (RTI); parotid lipomatosis, taste disturbance, xerostomia and perioral paraesthesia mainly related to PIs. Facial lipoatrophy is a common adverse effect of NRTIs; EM is more frequently associated with NNRTIs. Thus, although most of the more recent ART drugs and combinations of them show improved safety profiles, some may give rise to orofacial adverse effects, and may affect oral health care. © 2013 John Wiley & Sons A/S.

Sobrino A.,University of Santiago de Compostela
Studies in Fuzziness and Soft Computing | Year: 2012

The aim of this paper is to attempt a first approach to a kind of 'natural Fuzzy Prolog' based on the linguistic relations of synonymy and antonymy. Traditionally, Prolog was associated to the clausal logic, a disposition of the classical logic in which the goals are conjectural theorems and the answers, provided by the interpreter, are achieved using resolution and unification. Both resolution and unification are the core of a Prolog interpreter. Classical Prolog has had and still currently has interesting applications in domains as natural language processing where the problems are verbalized using crisp language and algorithmic style. But as Zadeh pointed out, natural language is essentially ill-defined or vague. Fuzzy Prolog provides tools for dealing with tasks that involve vague or imprecise statements and approximate reasoning. Traditionally, fuzzy Prolog was related with the specification of facts or rules as a matter of degree. Degrees adopted several forms: single degrees, intervals of degrees and linguistic truth-values, represented by triangular or trapezoidal numbers. Fuzzy solutions using degrees are valuable, but far from the way employed by human beings to solve daily problems. Using a naive style, this paper introduces a 'natural fuzzy Prolog' that deals with a kind of natural resolution applying antonymy as a linguistic negation and synonymy as a way to match predicates with similar meanings. © 2012 Springer-Verlag Berlin Heidelberg.