Seville, Spain
Seville, Spain

The University of Seville is a university in Seville, Spain. Founded under the name of Colegio Santa María de Jesús in 1505, it has a present student body of over 65,000, and is one of the top-ranked universities in the country. Seville is the 2000-year-old artistic, cultural, and financial capital of Andalusia in southern Spain; it is situated on the plain of the River Guadalquivir. Wikipedia.

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Anguiano M.,University of Seville | Suarez-Grau F.J.,University of Seville
Zeitschrift fur Angewandte Mathematik und Physik | Year: 2017

In this paper, we consider a non-Newtonian flow in a thin porous medium Ω ε of thickness ε which is perforated by periodically solid cylinders of size aε. The flow is described by the 3D incompressible Stokes system with a nonlinear viscosity, being a power of the shear rate (power law) of flow index 1 < p< + ∞. We consider the limit when domain thickness tends to zero, and we obtain different models depending on the magnitude aε with respect to ε. © 2017, Springer International Publishing.

Prieto F.,University of Seville | Alvarez-Malmagro J.,University of Seville | Rueda M.,University of Seville
Journal of Electroanalytical Chemistry | Year: 2017

The adsorption of the three adenine forms involved in two acid-base equilibria on Au(111) electrodes is studied by Electrochemical Impedance Spectroscopy. The experiments are performed in solutions of pH values 1, 7.5 and 12, at which the cationic, the neutral and the anionic adenine forms are present, respectively. Two adsorption models are adopted, both based on the theory of Frumkin and Melik-Gaykazyan for the adsorption process, but one of them takes also into account a deprotonation step preceding the adsorption step. The same frequency dependence of the impedance data is observed in the three pH media. The Nyquist admittance plots suggest a mixed kinetic control, by adsorption and by diffusion. The analysis of the electrode impedance or admittance as a function of the frequency according to the adsorption models provides the values of adsorption resistance, R ad, adsorption Warburg coefficient, σ ad and adsorption capacitance, C ad as a function of potential. From the σ advs E plot obtained at pH1 an equilibrium constant for adenine deprotonation at the vicinity of the electrode surface of c.a. 0.03 is calculated, which is three orders of magnitude higher than the equilibrium constant in the bulk solution. The different potential dependency of the adsorption rates at the three pH values is discussed on the basis of a Frumkin isotherm for the adsorption of adenine and a Butler-Volmer type potential dependence for the adsorption rate constant. © 2017 Elsevier B.V.

Gonzalez J.A.,University of Seville | Lee Y.-S.,Hongik University | Park K.C.,University of Colorado at Boulder
Computer Methods in Applied Mechanics and Engineering | Year: 2017

A mixed displacement–pressure formulation of the Stokes problem for incompressible fluids with free surfaces is developed for modeling the propagation of gravity waves in liquids and their interaction with structures using a Lagrangian approach. We assume that fluid displacements are small, making convective effects negligible and approximate the fluid velocities from the time derivative of the displacements. The resulting finite element equations are discretized with equal order for both displacement and pressure terms, together with employing stabilization techniques that circumvent the inf–sup requirements. The stability and accuracy of the methodology is finally demonstrated by solving some classical problems of hydrodynamics with free surfaces, comparing the results with known analytical solutions. © 2017 Elsevier B.V.

Arzac G.M.,University of Seville | Montes O.,University of Seville | Fernandez A.,University of Seville
Applied Catalysis B: Environmental | Year: 2017

We report the study of the catalytic hydrogen combustion over Pt-impregnated powdery silicon carbide (SiC) using H2PtCl6 as precursor. The reaction was conducted in excess of oxygen. β-SiC was selected for the study because of its thermal conductivity, mechanical properties, chemical inertness and surface area. The obtained Pt particles over SiC were medium size (average particle diameter of 5 nm for 0.5 wt% Pt). The activity of the Pt-impregnated catalyst over SiC was compared to those obtained in oxidized form over TiO2 and Al2O3 commercial supports (Pt particles very small in size, average particle diameter of 1 nm for 0.5 wt% Pt in both cases). The case of a SiO2 support was also discussed. Those Pt/SiC particles were the most active because of their higher contribution of surface Pt0, indicating that partially oxidized surfaces have better activity than those totally oxidized in these conditions. SiC was modified with an acid treatment and thus bigger (average particle diameter of 7 nm for 0.5 wt% Pt) and more active Pt particles were obtained. Durability of the SiC and TiO2 supported catalysts was tested upon 5 cycles and both have shown to be durable and even more active than initially. Exposure to the oxidative reaction mixture activates the catalysts and the effect is more pronounced for the completely oxidized particles. This is due to the surface oxygen chemisorption which activates catalystś surface. © 2016 Elsevier B.V.

Castillo-Lozano R.,University of Seville
Science and Sports | Year: 2017

Objective: The purpose of this study was to describe the incidence of musculoskeletal injuries in paddle-tennis senior players. Method: The sample was composed of 131 active paddle-tennis senior players (107 men/24 women); with a mean age of 56.8. ±. 4.6 years [50 to 66 years] and an average playtime of 9.4. ±. 6.3 years. Inclusion criteria were: practicing paddle-tennis more than 3 times per week or more than 5. hours weekly practice. Participants who met inclusion criteria were interviewed about their injuries playing a paddle-tennis (type of injury, place, time of recovery...) and completed the International physical activity questionnaire (IPAQ). Results: The results showed that the joint lesions due to paddle-tennis are located mainly in the elbow (29.8%), lower back (27.5%), knee (22.9%), ankle (22.1%) and shoulder (20.6%). Body mass index, laterality and age could explain between 14.2% and 68.5% of the variance of injuries in the paddle-tennis senior players. Conclusions: Paddle-tennis creates specific demands on the musculoskeletal system of senior players, with acute injuries such as knee sprains; while chronic overuse injuries, such as lateral epicondylitis, shoulder pain and low back pain. The main injury risk factors observed were age, laterality and body mass index. These findings could help physiotherapists to create preventive programmes. © 2017 Elsevier Masson SAS.

Ravoityte B.,Nature Research Center | Wellinger R.E.,University of Seville
Genes | Year: 2017

The division of prokaryotic and eukaryotic cells produces two cells that inherit a perfect copy of the genetic material originally derived from the mother cell. The initiation of canonical DNA replication must be coordinated to the cell cycle to ensure the accuracy of genome duplication. Controlled replication initiation depends on a complex interplay of cis-acting DNA sequences, the so-called origins of replication (ori), with trans-acting factors involved in the onset of DNA synthesis. The interplay of cis-acting elements and trans-acting factors ensures that cells initiate replication at sequence-specific sites only once, and in a timely order, to avoid chromosomal endoreplication. However, chromosome breakage and excessive RNA:DNA hybrid formation can cause break-induced (BIR) or transcription-initiated replication (TIR), respectively. These noncanonical replication events are expected to affect eukaryotic genome function and maintenance, and could be important for genome evolution and disease development. In this review, we describe the difference between canonical and non-canonical DNA replication, and focus on mechanistic differences and common features between BIR and TIR. Finally, we discuss open issues on the factors and molecular mechanisms involved in TIR. © 2017 by the authors; licensee MDPI, Basel, Switzerland.

Conde E.,University of Seville | Leal M.,University of Seville
Computers and Operations Research | Year: 2017

A new minmax regret optimization model in a system with uncertain parameters is proposed. In this model it is allowed to make investments before a minmax regret solution is implemented in order to modify the source or the nature of the existing uncertainty. Therefore, it is allowed to spend resources in order to change the basic cost structure of the system and take advantage of the modified system to find a robust solution. Some properties of this model allow us to have proper Mathematical Programming formulations that can be solved by standard optimization packages. As a practical application we consider the shortest path problem in a network in which it is possible to modify the uncertainty intervals for the arc costs by investing in the system. We also give an approximate algorithm and generalize some existing results on constant factor approximations. © 2017 Elsevier Ltd

Guerrero G.,Central University of Ecuador | Langa J.A.,University of Seville | Suarez A.,University of Seville
Nonlinear Analysis: Real World Applications | Year: 2017

A mathematical system of differential equations for the modelization of mutualistic networks in Ecology has been proposed in Bastolla et al. (2007). Basically, it is studied how the complex structure of cooperation interactions between groups of plants and pollinators or seed dispersals affects to the whole network. In this paper we prove existence and characterization of the global attractor associated to the model. The description of the geometrical internal structure of the attractor becomes the proper complex network describing all the possible future scenarios of the phenomena. The arguments show a Morse Decomposition of the attractors, leading to the existence of a global Lyapunov function for the associated gradient semigroup. In particular, we are able to prove topological structural stability of the system, i.e., the associated attracting complex networks are robust under (autonomous and non-autonomous) perturbation of parameters. © 2016 Elsevier Ltd

Nunez J.,University of Seville | Avedillo M.J.,University of Seville
IEEE Transactions on Nanotechnology | Year: 2017

Tunnel transistors are one of the most attractive steep subthreshold slope devices currently being investigated as a means of overcoming the power density and energy inefficiency limitations of CMOS technology. In this paper, the evaluation and the comparison of the performance of distinct fan-in logic gates, using a set of widely accepted power-speed metrics, are addressed for five projected tunnel transistor (TFET) technologies and four mosfet and FinFET transistors. The impact of logic depth, switching activity, and minimum supply voltage has been also included in our analysis. Provided results suggest that benefits in terms of a certain metric, in which a higher weight is placed on power or delay, are strongly determined by the selected device. Particularly, the suitability of two of the explored TFET technologies to improve CMOS performance for different metrics is pointed out. A circuit level benchmark is evaluated to validate our analysis. © 2016 IEEE.

Budarapu P.R.,Multi scale Analysis of Materials Research Unit | Reinoso J.,University of Seville | Paggi M.,Multi scale Analysis of Materials Research Unit
Computer Methods in Applied Mechanics and Engineering | Year: 2017

A solid shell-based adaptive atomistic–continuum numerical method is herein proposed to simulate complex crack growth patterns in thin-walled structures. A hybrid solid shell formulation relying on the combined use of the enhanced assumed strain (EAS) and the assumed natural strain (ANS) methods has been considered to efficiently model the material in thin structures at the continuum level. The phantom node method (PNM) is employed to model the discontinuities in the bulk. The discontinuous solid shell element is then concurrently coupled with a molecular statics model placed around the crack tip. The coupling between the coarse scale and the fine scale is realized through the use of ghost atoms, whose positions are interpolated from the coarse scale solution and enforced as boundary conditions to the fine scale model. In the proposed numerical scheme, the fine scale region is adaptively enlarged as the crack propagates and the region behind the crack tip is adaptively coarsened in order to reduce the computation costs. An energy criterion is used to detect the crack tip location. All the atomistic simulations are carried out using the LAMMPS software. A computational framework has been developed in MATLAB to trigger LAMMPS through system command. This allows a two way interaction between the coarse and fine scales in MATLAB platform, where the boundary conditions to the fine region are extracted from the coarse scale, and the crack tip location from the atomistic model is transferred back to the continuum scale. The developed framework has been applied to study crack growth in the energy minimization problems. Inspired by the influence of fracture on current–voltage characteristics of thin Silicon photovoltaic cells, the cubic diamond lattice structure of Silicon is used to model the material in the fine scale region, whilst the Tersoff potential function is employed to model the atom–atom interactions. The versatility and robustness of the proposed methodology is demonstrated by means of several fracture applications. © 2017 The Authors

Conde E.,University of Seville
Computers and Operations Research | Year: 2017

We consider an optimization problem in which the cost of a feasible solution depends on a set of unknown parameters (scenario) that will be realized. In order to assess the cost of implementing a given solution, its performance is compared with the optimal one under each feasible scenario. The positive difference between the objective values of both solutions defines the regret corresponding to a fixed scenario. The proposed optimization model will seek for a compromise solution by minimizing the expected regret where the expectation is taken respect to a probability distribution that depends on the same solution that is being evaluated, which is called solution-dependent probability distribution. We study the optimization model obtained by applying a specific family of solution-dependent probability distributions to the shortest path problem where the unknown parameters are the arc lengths of the network. This approach can be used to generate new models for robust optimization where the degree of conservatism is calibrated by using different families of probability distributions for the unknown parameters. © 2016 Elsevier Ltd

Fernandez-Navarro F.,University of Seville
Neural Processing Letters | Year: 2017

Ordinal regression is a kind of regression analysis used for predicting an ordered response variable. In these problems, the patterns are labelled by a set of ranks with an ordering among the different categories. The most common type of ordinal regression model is the cumulative link model. The cumulative link model relates an unobserved continuous latent variable with a monotone link function. Logit and probit functions are examples of link functions used in cumulative link models. In this paper, a novel generalized link function based on a generalization of the logistic distribution is proposed. The generalized link function proposed is able to reproduce other different link functions by changing two real parameters: (Formula presented.) and (Formula presented.). The generalized link function has been included in a cumulative link model where the latent function is determined by a standard neural network in order to test the performance of the proposal. For this model, a reformulation of the tunable thresholds and distribution parameters was applied to convert the constrained optimization problem into an unconstrained optimization problem. Experimental results demonstrate that our proposed approach can achieve competitive generalization performance. © 2017 Springer Science+Business Media New York

Fernandez-Viagas V.,University of Seville | Framinan J.M.,University of Seville
Computers and Operations Research | Year: 2017

The Permutation Flowshop Scheduling Problem with Makespan objective (PFSP-M) is known to be NP-hard for more than two machines, and literally hundreds of works in the last decades have proposed exact and approximate algorithms to solve it. These works—of computational/experimental nature—show that the PFSP-M is also empirically hard, in the sense that optimal or quasi-optimal sequences statistically represent a very small fraction of the space of feasible solutions, and that there are big differences among the corresponding makespan values. In the vast majority of these works, it has been assumed that (a) processing times are not job- and/or machine-correlated, and (b) all machines are initially available. However, some works have found that the problem turns to be almost trivial (i.e. almost every sequence yields an optimal or quasi-optimal solution) if one of these assumptions is dropped. To the best of our knowledge, no theoretical or experimental explanation has been proposed by this rather peculiar fact. Our hypothesis is that, under certain conditions of machine availability, or correlated processing times, the performance of a given sequence in a flowshop is largely determined by only one stage, thus effectively transforming the flowshop layout into a single machine. Since the single machine scheduling problem with makespan objective is a trivial problem where all feasible sequences are optimal, it would follow that, under these conditions, the equivalent PFSP-M is almost trivial. To address this working hypothesis from a general perspective, we investigate some conditions that allow reducing a permutation flowshop scheduling problem to a single machine scheduling problem, focusing on the two most common objectives in the literature, namely makespan and flowtime. Our work is a combination of theoretical and computational analysis, therefore several properties are derived to prove the conditions for an exact (theoretical) equivalence, together with an extensive computational evaluation to establish an empirical equivalence. © 2016 Elsevier Ltd

Hornedo-Ortega R.,University of Seville | Cerezo A.B.,University of Seville | Troncoso A.M.,University of Seville | Garcia-Parrilla M.C.,University of Seville | Mas A.,Rovira i Virgili University
Frontiers in Microbiology | Year: 2016

Yeast metabolism produces compounds derived from tryptophan, which are found in fermented beverages, such as wine and beer. In particular, melatonin and serotonin, may be relevant due to their bioactivity in humans. Indeed, the former is a neurohormone related to circadian rhythms, which also has a putative protective effect against degenerative diseases. Moreover, serotonin is a neurotransmitter itself, in addition to being a precursor of melatonin synthesis. This paper summarizes data reported on fermented beverages, to evaluate dietary intake. Additionally, the article reviews observed effects of yeast amino acid metabolites on the prevention of neurodegenerative diseases (Alzheimer's and Parkinson's) and angiogenesis, focusing on evidence of the molecular mechanism involved and identification of molecular targets. © 2016 Hornedo-Ortega, Cerezo, Troncoso, Garcia-Parrilla and Mas.

Valverde J.M.,University of Seville | Medina S.,University of Seville
Physical Chemistry Chemical Physics | Year: 2017

This work reports an in situ XRD analysis of whether the calcination/carbonation behavior of natural limestone (CaCO3) is affected by the addition of H2O to the calciner at a very low concentration under relevant Calcium-Looping (CaL) conditions for CO2 capture in coal fired power plants (CFPP) and Thermochemical Energy Storage (TCES) in Concentrated Solar Power plants (CSP). Previous studies have demonstrated that the presence of steam in the calciner at a high concentration yields a significant increase in the reaction rate. However, a further undesired consequence is the serious deterioration of the CaO mechanical strength, which would lead to particle attrition and mass loss in any CaL process based on the use of circulating fluidized beds. The results presented in this manuscript on the time evolution of the wt% and crystallite size of the phases involved in the calcination/carbonation reactions indicate that the calcination rate is still notably increased by the presence of H2O at very low concentrations whereas the reactivity toward carbonation and crystal structure of the formed CaO are not essentially affected, which suggests that the CaO mechanical strength is not impaired. Thus, the benefit of using steam for calcination in the CaL process could be still retained while at the same time particle attrition would not be promoted. © the Owner Societies 2017.

Gomez-Ramos M.,University of Seville | Moro A.M.,University of Seville
Physical Review C | Year: 2017

Background: Reactions involving weakly bound nuclei require formalisms able to deal with continuum states. The majority of these formalisms struggle to treat collective excitations of the systems involved. For continuum-discretized coupled channels (CDCC), extensions to include target excitation have been developed but have only been applied to a small number of cases. Purpose: In this work, we reexamine the extension of the CDCC formalism to include target excitation and apply it to a variety of reactions to study the effect of breakup on inelastic cross sections. Methods: We use a transformed oscillator basis to discretize the continuum of the projectiles in the different reactions and use the extended CDCC method developed in this work to solve the resulting coupled differential equations. A new code has been developed to perform the calculations. Results: Reactions Ni58(d,d)Ni∗58, Mg24(d,d)Mg∗24, Sm144(Li6,Li6)Sm∗144, and Be9(Li6,Li6)Be∗9 are studied. Satisfactory agreement is found between experimental data and extended CDCC calculations. Conclusions: The studied CDCC method has proven to be an accurate tool to describe target excitation in reactions with weakly bound nuclei. Moderate effects of breakup on inelastic observables are found for the reactions studied. Cross-section magnitudes are not modified much, but angular distributions present smoothing when opposed to calculations without breakup. © 2017 American Physical Society.

Rull L.F.,University of Seville | Romero-Enrique J.M.,University of Seville
Molecular Physics | Year: 2017

We present computer simulations of the vapour–nematic interface of the Gay–Berne model. We considered situations which correspond to either prolate or oblate molecules. We determine the anchoring of the nematic phase and correlate it with the intermolecular potential parameters. On the other hand, we evaluate the surface tension associated to this interface. We find a corresponding states law for the surface tension dependence on the temperature, valid for both prolate and oblate molecules. © 2017 Informa UK Limited, trading as Taylor & Francis Group

Exposito A.,University of Seville | Berbel J.,University of Cordoba, Spain
Water (Switzerland) | Year: 2017

This paper analyses the agricultural irrigation water use in a closed basin and the impacts on water productivity, and examines how they have affected the 'closure' process of the Guadalquivir river basin observed in recent decades. Following a period of expansion in irrigation, an administrative moratorium was declared on new irrigated areas in 2005. Since then, the main policy measure has been aimed at the modernisation of irrigated agriculture and the implementation of water conservation technologies. The analysis carried out in this paper shows a significant increase in mean irrigation water productivity in the pre-moratorium period (1989-2005), driven by the creation of new irrigated areas devoted to high value crops and with a dominant use of deficit irrigation strategies, while a second phase (2005-2012) is characterised by slower growth in terms of the mean productivity of irrigation water, primarily as a result of a significant reduction in water use per area. Findings show that productivity gains seem to have reached a ceiling in this river basin, since technological innovations (such as new crops, deficit irrigation, and water-saving and conservation technologies) have reached the limits of their capacity to create new value. © 2017 by the authors.

Vidal R.,University of Seville
Applied Microbiology and Biotechnology | Year: 2017

The protein AdhA from the cyanobacterium Synechocystis sp. PCC 6803 (hereafter Synechocystis) has been previously reported to show alcohol dehydrogenase activity towards ethanol and both NAD and NADP. This protein is currently being used in genetically modified strains of Synechocystis capable of synthesizing ethanol showing the highest ethanol productivities. In the present work, mutant strains of Synechocystis lacking AdhA have been constructed and tested for tolerance to ethanol. The lack of AdhA in the wild-type strain reduces survival to externally added ethanol at lethal concentration of 4% (v/v). On the other hand, the lack of AdhA in an ethanologenic strain diminishes tolerance of cells to internally produced ethanol. It is also shown that light-activated heterotrophic growth (LAHG) of the wild-type strain is impaired in the mutant strain lacking AdhA (∆adhA strain). Photoautotrophic, mixotrophic, and photoheterotrophic growth are not affected in the mutant strain. Based on phenotypic characterization of ∆adhA mutants, the possible physiological function of AdhA in Synechocystis is discussed. © 2017 Springer-Verlag Berlin Heidelberg

Framinan J.M.,University of Seville | Perez-Gonzalez P.,University of Seville
Computers and Operations Research | Year: 2017

In this paper, we study a customer order scheduling problem where a number of orders, composed of several product types, have to be scheduled on a set of parallel machines, each one capable to process a single product type. The objective is to minimise the sum of the completion times of the orders, which is related to the lead time perceived by the customer, and also to the minimisation of the work-in-process. This problem has been previously studied in the literature, and it is known to be NP-hard even for two product types. As a consequence, the interest lies on devising approximate procedures to obtain fast, good performing schedules. Among the different heuristics proposed for the problem, the ECT (Earliest Completion Time) heuristic by Leung et al. [6] has turned to be the most efficient constructive heuristic, yielding excellent results in a wide variety of settings. These authors also propose a tabu search procedure that constitutes the state-of-the-art metaheuristic for the problem. We propose a new constructive heuristic based on a look-ahead mechanism. The computational experience conducted shows that it clearly outperforms ECT, while having both heuristics the same computational complexity. Furthermore, we propose a greedy search algorithm using a specific neighbourhood that outperforms the existing tabu search procedure for different stopping criteria, both in terms of quality of solutions and of required CPU effort. © 2016 Elsevier Ltd

Labbe M.,Free University of Colombia | Ponce D.,University of Seville | Puerto J.,University of Seville
Computers and Operations Research | Year: 2017

This paper presents several new formulations for the Discrete Ordered Median Problem (DOMP) based on its similarity with some scheduling problems. Some of the new formulations present a considerably smaller number of constraints to define the problem with respect to some previously known formulations. Furthermore, the lower bounds provided by their linear relaxations improve the ones obtained with previous formulations in the literature even when strengthening is not applied. We also present a polyhedral study of the assignment polytope of our tightest formulation showing its proximity to the convex hull of the integer solutions of the problem. Several resolution approaches, among which we mention a branch and cut algorithm, are compared. Extensive computational results on two families of instances, namely randomly generated and from Beasley's OR-library, show the power of our methods for solving DOMP. © 2016 Elsevier Ltd

Marques R.,University of Seville | Hernandez-Herrador V.,Independent Consultant
Accident Analysis and Prevention | Year: 2017

We analyze the evolution of the risk of cycling in Seville before and after the implementation of a network of segregated cycle tracks in the city. Specifically, we study the evolution of the risk for cyclists of being involved in a collision with a motor vehicle, using data reported by the traffic police along the period 2000–2013, i.e. seven years before and after the network was built. A sudden drop of such risk was observed after the implementation of the network of bikeways. We study, through a multilinear regression analysis, the evolution of the risk by means of explanatory variables representing changes in the built environment, specifically the length of the bikeways and a stepwise jump variable taking the values 0/1 before/after the network was implemented. We found that this last variable has a high value as explanatory variable, even higher than the length of the network, thus suggesting that networking the bikeways has a substantial effect on cycling safety by itself and beyond the mere increase in the length of the bikeways. We also analyze safety in numbers through a non-linear regression analysis. Our results fully agree qualitatively and quantitatively with the results previously reported by Jacobsen (2003), thus providing an independent confirmation of Jacobsen's results. Finally, the mutual causal relationships between the increase in safety, the increase in the number of cyclists and the presence of the network of bikeways are discussed. © 2017 Elsevier Ltd

Miranda-Pizarro J.,University of Seville
Fuel | Year: 2017

The Calcium Looping (CaL) process, based on the cyclic carbonation/calcination of CaO, has emerged in the last years as a potentially low cost technique for CO2 capture at reduced energy penalty. In the present work, natural limestone and dolomite have been pretreated with diluted acetic acid to obtain Ca and Ca-Mg mixed acetates, whose CO2 capture performance has been tested at CaL conditions that necessarily imply sorbent regeneration under high CO2 partial pressure. The CaL multicycle capture performance of these sorbents has been compared with that of CaO directly derived from limestone and dolomite calcination. Results show that acetic acid pretreatment of limestone does not lead to an improvement of its capture capacity, although it allows for a higher calcination efficiency to regenerate CaO at reduced temperatures (∼900 °C) as compared to natural limestone (>∼930 °C). On the other hand, if a recarbonation stage is introduced before calcination to reactivate the sorbent, a significantly higher residual capture capacity is obtained for the Ca-Mg mixed acetate derived from dolomite as compared to either natural dolomite or limestone. The main reason for this behavior is the enhancement of carbonation in the solid-state diffusion controlled phase. It is argued that the presence of inert MgO grains in the mixed acetate with reduced segregation notably promotes solid state diffusion of ions across the porous structure created after recarbonation. © 2017 Elsevier Ltd

Campos J.,University of Seville
Journal of the American Chemical Society | Year: 2017

The first example of a frustrated Lewis pair (FLP) solely constructed around transition metal centers is described in this work. We have focused on the established capacity of Au(I) and Pt(0) complexes to act as Lewis acidic and basic fragments, respectively, while employing sufficiently bulky PtBu3 and terphenyl phosphine ligands. This avoids formation of metallic Lewis adducts and confers the Au(I)/Pt(0) pair a remarkable capacity to activate dihydrogen and acetylene molecules in a fashion that closely resembles that of traditional main group FLP systems. As a consequence, unusual heterobimetallic Au(I)/Pt(II) complexes containing hydride (−H), acetylide (−CCH), and vinylene (−HCCH−) bridges have been isolated. © 2017 American Chemical Society.

Morales-Padron M.P.,University of Seville
Revista de Obras Publicas | Year: 2017

The present article provides a historical overview of the construction of the San Telmo bridge, describing its background and impact on the inland port of Seville. This relation with the port remained intact until the machinery used to raise the bridge was removed at the start of the nineteen sixties and port activity was moved far away from the ancient wharves of the Arenal.

Suarez-de Vivero J.L.,University of Seville | Rodriguez Mateos J.C.,University of Seville
Marine Policy | Year: 2017

The publication of reports on geo-political risks in the world sponsored by intelligence agencies, university institutes and think tanks are valuable instruments in societies that are being increasingly exposed to the effects of globalisation. Although all express mention of geo-political risks of a maritime nature is absent from these documents, it is an interesting exercise to determine: i) Which geo-political risks or threats have a maritime dimension or imply derivations whose occurrence may be linked to maritime space? ii) Which processes or tendencies in the use, occupation and governance of maritime space can fall into the category of geo-political risk? The basic aim is to address the forms that instability and geo-political risks take in the ocean world. If the risks stated in the chosen literature are examined from the maritime perspective, it is possible to perceive ‘secondary’ risks whose size and reach can become major contingencies for international stability. They therefore should not be ignored in the prognosis and evaluation of geo-political risks. In as much as societies' political organisation continues to rest on the nation-State, the dominance of the maritime component in the territorial basis is a permanent source of tensions and conflicts. In parallel with this, the displacement of economic expectations and the supply of traditional and new resources to the marine environment broadens the spectrum of risks and threats. © 2016 Elsevier Ltd

de Ponte M.,University of Seville
Journal of Pragmatics | Year: 2017

In this paper, I discuss explicit performative sentences and, in particular, those containing the explicit performative verb “to promise.” I argue that one of the key features of explicit performative verbs is their utterance-reflexive character. In a minimal context, an utterance like “I promise I will finish the paper” can be taken either as an explicit performative utterance, a promise, or as an assertion, which does not constitute a promise but a report of one. An utterance like “I promise now I will finish the paper,” however, in a minimal context, should be taken as an explicit performative. To explain this, I use Prior and Kamp's work on “now” (Prior, 1968; Kamp, 1971) and Korta and Perry's content pluralism (Korta and Perry, 2011). I defend that the role “now” plays when embedded in a performative sentence is consistent with the role it plays when embedded in a temporal operator. In both cases, the role of “now” is to reflexively point to the time of utterance and in neither case is the “now” redundant. © 2017 Elsevier B.V.

Duran A.J.,University of Seville
Journal of Mathematical Analysis and Applications | Year: 2017

We show how to get Krall polynomials from Krall discrete polynomials using a procedure of passing to the limit in some of the parameters of the family. We also show that this procedure has to be different to the standard one used in the Askey scheme to go from the classical discrete polynomials to the classical polynomials. © 2017 Elsevier Inc.

Aparicio-Soto M.,University of Seville | Sanchez-Hidalgo M.,University of Seville | Alarcon-de-la-Lastra C.,University of Seville
Nutrition Research Reviews | Year: 2017

Systemic lupus erythematosus (SLE) is a chronic inflammatory and autoimmune disease characterised by multiple organ involvement and a large number of complications. SLE management remains complicated owing to the biological heterogeneity between patients and the lack of safe and specific targeted therapies. There is evidence that dietary factors can contribute to the geoepidemiology of autoimmune diseases such as SLE. Thus, diet therapy could be a promising approach in SLE owing to both its potential prophylactic effects, without the side effects of classical pharmacology, and its contribution to reducing co-morbidities and improving quality of life in patients with SLE. However, the question arises as to whether nutrients could ameliorate or exacerbate SLE and how they could modulate inflammation and immune function at a molecular level. The present review summarises preclinical and clinical experiences to provide the reader with an update of the positive and negative aspects of macro- and micronutrients and other nutritional factors, including dietary phenols, on SLE, focusing on the mechanisms of action involved. Copyright © The Authors 2017

Framinan J.M.,University of Seville | Perez-Gonzalez P.,University of Seville
Proceedings - Winter Simulation Conference | Year: 2017

This paper focuses on Available-To-Promise (ATP) systems in the semiconductor industry. These systems have been successfully applied in a number of sectors, although it is often mentioned that their advantages increase with the ability of obtaining accurate forecasts, and with the possibility of identifying a relatively large number of different customers or customer classes. These conditions do not necessarily fulfil in the semiconductor industry, therefore it is interesting to analyse the few case studies of these systems that have been presented in the literature. A preliminary experiment is carried out using a foundry plant data to investigate the influence of the forecast accuracy and forecast bias in the performance of these systems. The results highlight the problems caused by the lack of homogeneity in the forecast, and the distortion introduced by customers 'inflating' their projected demand in order to ensure a higher share of the orders. © 2016 IEEE.

De La Rosa J.M.,University of Seville
2016 IEEE International Conference on Electron Devices and Solid-State Circuits, EDSSC 2016 | Year: 2016

This paper presents a tutorial guide for the systematic design of ΣΔ Modulators-from system-level specifications to circuit-level design and silicon implementation. The whole design flow is outlined and illustrated by several case studies and chip examples intended for reconfigurable ADCs in multi-standard wireless telecom systems1. © 2016 IEEE.

Sanchez-Moyano J.E.,University of Seville | Garcia-Asencio I.,University of Seville
Marine Pollution Bulletin | Year: 2010

The spatial-temporal variation in crustacean assemblages of the Odiel-Tinto estuary, one of the most polluted areas in the world, was studied in 2000, 2002 and 2004. The crustacean assemblages were mainly established according to the natural gradient from estuarine to marine environment (based on water and sediment characteristics such as dissolved oxygen, salinity, granulometry or organic content). Pollutants such as copper, zinc or phosphates could also explain partially this pattern based on BIOENV and canonical correspondence analyses. However, there were clear symptoms of perturbation, mainly in the inner areas, such as a low number of species and a low abundance, especially in relation to the typical estuarine species (e.g. Cyathura carinata, Corophium spp.). This study provides baseline information which can be used as a reference point in a long-term perspective. © 2010 Elsevier Ltd.

Gutierrez Ortiz F.J.,University of Seville
Applied Thermal Engineering | Year: 2011

In fire-tube boilers, the flue gas passes inside boiler tubes, and heat is transferred to water on the shell side. A dynamic model has been developed for the analysis of boiler performance, and Matlab has been applied for integrating it. The mathematical model developed is based on the first principles of mass, energy and momentum conservations. In the model, the two parts of the boiler (fire/gas and water/steam sides), the economizer, the superheater and the heat recovery are considered. The model developed can capture the dynamics of the boiler level and boiler pressure with confidence, and it is adequate to approach the boiler performance and, hence, to design and test a control strategy for such boilers. Furthermore, it gives insight of dynamics performance not only during nominal operating conditions, or transient behavior when a parameter is changed, but also for the start-up. The model proposed can be easily implemented and thus, it is useful to assist plant engineers and even for training future operators. A case study of an 800 HP fire-tube boiler burning fuel-oil has been simulated to test the boiler performance by varying operating conditions using a pulse and a step change in fuel and steam flow-rate as well as simulating a start-up form the beginning up to achieve the steady state. The results match qualitatively well when compared to results from the literature. © 2011 Elsevier Ltd.

Sanchez-De-Armas R.,University of Seville | Oviedo J.,University of Seville | San Miguel M.A.,University of Seville | Sanz J.F.,University of Seville
Journal of Physical Chemistry C | Year: 2011

Dye-sensitized solar cells based on organic dyes have attracted considerable attention in recent years. These dyes present important differences in geometry and electronic structure, and diverse mechanisms for electronic injection into semiconductor conduction band have been reported. In this work, the electronic structure and the optical response of several dyes, free and bound to TiO2, have been analyzed and compared using time-dependent density functional theory (TD-DFT) performing calculations both in real time and frequency domains. The aim is to illustrate which aspects of each sensitizer produce different electron injection mechanisms. From the analysis it is concluded that for adsorbed NKX-2311, a coumarin based dye, the photoexcitation occurs toward an orbital mainly localized on the molecule, so this molecule is classified as a type I sensitizer, which follows an indirect mechanism for electron injection. In contrast, catechol and 2,3-naphthalenediol are type II sensitizers and follow a direct mechanism for injecting electrons into the TiO2 conduction band. In this case, a new band appears in the spectrum, which corresponds to a photoexcitation from states fully localized on the dye to states mainly localized on the cluster but with appreciable dye contribution. NKX-2311 and catechol show limit behaviors. Nevertheless, intermediate ones are also possible. As we move in the sequence catechol, 2,3-naphthalenediol, C343, alizarin, and NKX-2311, we pass progressively from a purely direct injection mechanism to a purely indirect injection mechanism. This is related to the relative position of the molecule LUMO energy to the edge of the semiconductor conduction band. © 2011 American Chemical Society.

Munoz M.,University of Seville | Covenas R.,University of Salamanca
Peptides | Year: 2013

Many data suggest the deep involvement of the substance P (SP)/neurokinin (NK)-1 receptor system in cancer: (1) Tumor cells express SP, NK-1 receptors and mRNA for the tachykinin NK-1 receptor; (2) Several isoforms of the NK-1 receptor are expressed in tumor cells; (3) the NK-1 receptor is involved in the viability of tumor cells; (4) NK-1 receptors are overexpressed in tumor cells in comparison with normal ones and malignant tissues express more NK-1 receptors than benign tissues; (5) Tumor cells expressing the most malignant phenotypes show an increased percentage of NK-1 receptor expression; (6) The expression of preprotachykinin A is increased in tumor cells in comparison with the levels found in normal cells; (7) SP induces the proliferation and migration of tumor cells and stimulates angiogenesis by increasing the proliferation of endothelial cells; (8) NK-1 receptor antagonists elicit the inhibition of tumor cell growth; (9) The specific antitumor action of NK-1 receptor antagonists on tumor cells occurs through the NK-1 receptor; (10) Tumor cell death is due to apoptosis; (11) NK-1 receptor antagonists inhibit the migration of tumor cells and neoangiogenesis. The NK-1 receptor is a therapeutic target in cancer and NK-1 receptor antagonists could be considered as broad-spectrum antitumor drugs for the treatment of cancer. It seems that a common mechanism for cancer cell proliferation mediated by SP and the NK-1 receptor is triggered, as well as a common mechanism exerted by NK-1 receptor antagonists on tumor cells, i.e. apoptosis. © 2013 Elsevier Inc. All rights reserved.

Garcia Rivero D.,University of Seville | O'Brien M.J.,University of Missouri
PLoS ONE | Year: 2014

Prehistoric material culture proposed to be symbolic in nature has been the object of considerable archaeological work from diverse theoretical perspectives, yet rarely are methodological tools used to test the interpretations. The lack of testing is often justified by invoking the opinion that the slippery nature of past human symbolism cannot easily be tackled by the scientific method. One such case, from the southwestern Iberian Peninsula, involves engraved stone plaques from megalithic funerary monuments dating ca. 3,500-2,750 B.C. (calibrated age). One widely accepted proposal is that the plaques are ancient mnemonic devices that record genealogies. The analysis reported here demonstrates that this is not the case, even when the most supportive data and techniques are used. Rather, we suspect there was a common ideological background to the use of plaques that overlay the southwestern Iberian Peninsula, with little or no geographic patterning. This would entail a cultural system in which plaque design was based on a fundamental core idea, with a number of mutable and variable elements surrounding it. © 2014 García Rivero, O'Brien.

Martinez-Alvarez F.,Pablo De Olavide University | Troncoso A.,Pablo De Olavide University | Riquelme J.C.,University of Seville | Aguilar Ruiz J.S.,Pablo De Olavide University
IEEE Transactions on Knowledge and Data Engineering | Year: 2011

This paper presents a new approach to forecast the behavior of time series based on similarity of pattern sequences. First, clustering techniques are used with the aim of grouping and labeling the samples from a data set. Thus, the prediction of a data point is provided as follows: first, the pattern sequence prior to the day to be predicted is extracted. Then, this sequence is searched in the historical data and the prediction is calculated by averaging all the samples immediately after the matched sequence. The main novelty is that only the labels associated with each pattern are considered to forecast the future behavior of the time series, avoiding the use of real values of the time series until the last step of the prediction process. Results from several energy time series are reported and the performance of the proposed method is compared to that of recently published techniques showing a remarkable improvement in the prediction. © 2011 IEEE.

Castillo-Manzano J.I.,University of Seville | Lopez-Valpuesta L.,University of Seville
Journal of Air Transport Management | Year: 2014

This paper uses a large database of approximately 37,000 passengers and three different estimates to analyse the characteristics of the frequent flyer and the differences between frequent flyers and occasional flyers. The results show that frequent flyers are middle-aged men with a high level of education who take domestic flights for business reasons at both hub and regional airports, where they make a purchase and/or consume F&B. Frequent flyers fly on both low-cost and traditional airlines, are more likely to stay overnight at a relative's or friend's home and travel to the airport by private or rented car. © 2014 Elsevier Ltd.

Cordoba-Fernandez A.,University of Seville
Journal of the American Podiatric Medical Association | Year: 2012

Interphalangeal joint dislocations of the lesser toes are relatively rare in clinical practice. Most nonreducible interphalangeal joint dislocations occur as a result of rupture or interposition of the plantar plate or of the collateral ligament in the joint space, thus hindering a closed reduction and, in most cases, compelling an open reduction. A post-reduction radiologic exploration is then essential to identify such an entity and proceed consequently. In some cases, such as the one introduced herein, a misdiagnosis, along with an inadequate surgical correction may lead to recurrence of the deformity and, ultimately, to a salvage arthrodesis.

Tierra G.,Charles University | Guillen-Gonzalez F.,University of Seville
Archives of Computational Methods in Engineering | Year: 2015

In this paper, we review some numerical methods presented in the literature in the last years to approximate the Cahn–Hilliard equation. Our aim is to compare the main properties of each one of the approaches to try to determine which one we should choose depending on which are the crucial aspects when we approximate the equations. Among the properties that we consider desirable to control are the time accuracy order, energy-stability, unique solvability and the linearity or nonlinearity of the resulting systems. In particular, we concern about the iterative methods used to approximate the nonlinear schemes and the constraints that may arise on the physical and computational parameters. Furthermore, we present the connections of the Cahn–Hilliard equation with other physically motivated systems (not only phase field models) and we state how the ideas of efficient numerical schemes in one topic could be extended to other frameworks in a natural way. © 2014, CIMNE, Barcelona, Spain.

Fernandez-Viagas V.,University of Seville | Framinan J.M.,University of Seville
Computers and Operations Research | Year: 2015

Since Johnson's seminal paper in 1954, scheduling jobs in a permutation flowshop has been receiving the attention of hundreds of practitioners and researchers, being one of the most studied topics in the Operations Research literature. Among the different objectives that can be considered, minimising the total tardiness (i.e. the sum of the surplus of the completion time of each job over its due date) is regarded as a key objective for manufacturing companies, as it entails the fulfilment of the due dates committed to customers. Since this problem is known to be NP-hard, most research has focused on proposing approximate procedures to solve it in reasonable computation times. Particularly, several constructive heuristics have been proposed, with NEHedd being the most efficient one, serving also to provide an initial solution for more elaborate approximate procedures. In this paper, we first analyse in detail the decision problem depending on the generation of the due dates of the jobs, and discuss the similarities with different related decision problems. In addition, for the most characteristic tardiness scenario, the analysis shows that a huge number of ties appear during the construction of the solutions done by the NEHedd heuristic, and that wisely breaking the ties greatly influences the quality of the final solution. Since no tie-breaking mechanism has been designed for this heuristic up to now, we propose several mechanisms that are exhaustively tested. The results show that some of them outperform the original NEHedd by about 25% while keeping the same computational requirements. © 2015 Elsevier Ltd. All rights reserved.

Fernandez-Viagas V.,University of Seville | Framinan J.M.,University of Seville
Computers and Operations Research | Year: 2015

This paper addresses the problem of scheduling jobs in a permutation flowshop with the objective of total completion time minimisation. Since this problem is known to be NP-hard, most research has focussed on obtaining procedures - heuristics - able to provide good, but not necessarily optimal, solutions with a reasonable computational effort. Therefore, a full set of heuristics efficiently balancing both aspects (quality of solutions and computational effort) has been developed. 12 out of these 14 efficient procedures are composite heuristics based on the LR heuristic by Liu and Reeves (2001), which is of complexity n3m. In our paper, we propose a new heuristic of complexity n2m for the problem, which turns out to produce better results than LR. Furthermore, by replacing the heuristic LR by our proposal in the aforementioned composite heuristics, we obtain a new set of 17 efficient heuristics for the problem, with 15 of them incorporating our proposal. Additionally, we also discuss some issues related to the evaluation of efficient heuristics for the problem and propose an alternative indicator. © 2014 Elsevier Ltd.

Objective: To describe the presence of women in the governance of health-related scientific societies in Spain today. Methods: Spanish scientific societies were identified by vising the websites of the Ministry of Health, Social Services and Equality, and Fisterra. The sex of the president, executive officers and the board of directors was identified. Data were analyzed according to the overall percentage of women and by profession and setting. Results: Of 173 scientific societies in July 2014, 41 had a female president (22.53%). Women held 35.45% of executive positions and accounted for 36.32% of the boards of directors. Only 16.07% of medical societies had a female president compared with 76.92% of nursing societies. Primary care societies had more women in executive positions (54.55%) than societies in which the professional activity of members involved both primary and secondary care (35.74%) and societies related to hospital care (27.93%). Conclusion: There is a lack of parity, which is greater in nursing and primary care societies than in medical and hospital-related societies. Parity decreases as the level of responsibility rises. © 2014 SESPAS.

Gomez-Piriz P.T.,University of Seville | JimeNez-Reyes P.,University of Seville | Ruiz-Ruiz C.,University of Seville
Journal of Strength and Conditioning Research | Year: 2011

Gomez-Piriz, PT, Jiménez-Reyes, P, and Ruiz-Ruiz, C. Relation between total body load and Session-RPE in professional soccer players. J Strength Cond Res 25(8): 2100-2103, 2011-The aims of this study were to assess (a) the validity of total body load (TBL)-obtained from the global position system (GPS) devices-to quantify soccer training load, assessing its relationship with session rating of perceived exertion (session-RPE) and (b) to analyze the differences in terms of TBL and session-RPE among defenders, midfielders, and forwards. Twenty-two professional soccer players (Spanish first division, season 2007-2008; 26.74 ± 4.2 years; height 179.74 ± 4.04 cm; weight 73.7 ± 3.35 kg) participated in the study. During 13 training sessions composed predominantly of small-sided games, TBL and RPE multiplied by the minutes of session duration were determined using GPS and the 21-point scale, respectively. In each session, data from 10 players randomly selected and classified according to player position (defenders, midfielders, and forwards) were collected. Although session-RPE was a significant predictor of TBL (β = 0.23, p < 0.05), this method only accounted for 5% of the variance in TBL. No significant differences in terms of TBL and session-RPE were found regarding player position. The results of this study suggest that TBL is not a valid measure to quantify training load because it is not strongly correlated with session-RPE. Furthermore, TBL and session-RPE in small-sided soccer games do not vary according to player positions. © 2011 National Strength and Conditioning Association.

Goder V.,University of Seville
Current Protein and Peptide Science | Year: 2012

In the secretory pathway, quality control for the correct folding of proteins is largely occurring in the endoplasmic reticulum (ER), at the earliest possible stage and in an environment where early folding intermediates mix with terminally misfolded species. An elaborate cellular mechanism aims at dividing the former from the latter and promotes the selective transport of misfolded species back into the cytosol, a step called retrotranslocation. During retrotranslocation proteins will become ubiquitinated on the cytosolic side of the ER membrane by dedicated machineries and will be targeted to the proteasome for degradation. The entire process, from protein recognition to final degradation, has been named ER-associated protein degradation, or simply ERAD. Ubiquitin has well known functions in aiding late steps of substrate retrotranslocation and in targeting substrates to the proteasome. Recent results show that several cytosolic machineries allow ubiquitinated substrates to undergo extensive remodeling, or processing, on their poly-ubiquitin chains (PUCs). Although still ill-defined, PUC processing might have a unique function for ERAD in that it might provide a mechanism to generate optimal PUCs for recognition by proteasomal ubiquitin receptors. Ubiquitination might also have a previously unanticipated role in quality control of ER membrane proteins. This review recapitulates the current knowledge and recent findings about ERAD-specific roles of ubiquitin. © 2012 Bentham Science Publishers.

Badia S.,Polytechnic University of Catalonia | Guillen-Gonzalez F.,University of Seville | Gutierrez-Santacreu J.V.,University of Seville
Journal of Computational Physics | Year: 2011

In this work, we propose finite element schemes for the numerical approximation of nematic liquid crystal flows, based on a saddle-point formulation of the director vector sub-problem. It introduces a Lagrange multiplier that allows to enforce the sphere condition. In this setting, we can consider the limit problem (without penalty) and the penalized problem (using a Ginzburg-Landau penalty function) in a unified way. Further, the resulting schemes have a stable behavior with respect to the value of the penalty parameter, a key difference with respect to the existing schemes. Two different methods have been considered for the time integration. First, we have considered an implicit algorithm that is unconditionally stable and energy preserving. The linearization of the problem at every time step value can be performed using a quasi-Newton method that allows to decouple fluid velocity and director vector computations for every tangent problem. Then, we have designed a linear semi-implicit algorithm (i.e. it does not involve nonlinear iterations) and proved that it is unconditionally stable, verifying a discrete energy inequality. Finally, some numerical simulations are provided. © 2010 Elsevier Inc.

Lozano S.,University of Seville | Gutierrez E.,University of Seville
Networks and Spatial Economics | Year: 2011

In this paper an efficiency analysis of 41 Spanish airports is carried out. A description of the physical infrastructure of the airports, namely total runway area, apron capacity, passenger throughput capacity, number of baggage belts, number of check-in counters and number of boarding gates, is used as inputs. Air Traffic Movements, Passenger Movements and Cargo handled are used as outputs. An output-oriented, Variable-Returns-to-Scale, non-radial Data Envelopment Analysis (DEA) model is used to compute the Russell measure of output technical efficiency. Half of the airports are found technically efficient. Scale efficiency and local Returns to Scale have also been assessed, indicating that except for a few airports that operate at their Most Productive Scale Size, for most Spanish airports Increasing Returns to Scale prevail. An original DEA model for target setting and scenario analysis is also proposed. The model uses two parameters (Plane Load Factor and Passenger/Cargo Ratio) that allow the relating of two of the outputs to the third. The model computes efficient targets given the value of these two parameters and the vector of available inputs. The results of this target-setting DEA model for Seville airport for different values of the two parameters and different future input scenarios are presented. © 2009 Springer Science+Business Media, LLC.

Lopez-Herrera J.M.,University of Seville | Popinet S.,NIWA - National Institute of Water and Atmospheric Research | Herrada M.A.,University of Seville
Journal of Computational Physics | Year: 2011

In the present study we propose a charge-conservative scheme to solve two-phase electrohydrodynamic (EHD) problems using the volume-of-fluid (VOF) method. EHD problems are usually simplified by assuming that the fluids involved are purely dielectric (insulators) or purely conducting. Gases can be considered as perfect insulators but pure dielectric liquids do not exist in nature and insulating liquids have to be approximated using the " Taylor-Melcher leaky dielectric model" [1,2] in which a leakage of charge through the liquid due to ohmic conduction is allowed. It is also a customary assumption to neglect the convection of charge against the ohmic conduction. The scheme proposed in this article can deal with any EHD problem since it does not rely on any of the above simplifications. An unrestricted EHD solver requires not only to incorporate electric forces in the Navier-Stokes equations, but also to consider the charge migration due to both conduction and convection in the electric charge conservation equation [3]. The conducting or insulating nature of the fluids arise on their own as a result of their electric and fluid mechanical properties. The EHD solver has been built as an extension to Gerris, a free software solver for the solution of incompressible fluid motion using an adaptive VOF method on octree meshes developed by Popinet [4,5]. © 2010 Elsevier Inc.

Pascual M.B.,University of Seville | Mata-Cabana A.,University of Seville | Florencio F.J.,University of Seville | Lindahl M.,University of Seville | Cejudo F.J.,University of Seville
Journal of Biological Chemistry | Year: 2010

In eukaryotic organisms, hydrogen peroxide has a dual effect; it is potentially toxic for the cell but also has an important signaling activity. According to the previously proposed floodgate hypothesis, the signaling activity of hydrogen peroxide in eukaryotes requires a transient increase in its concentration, which is due to the inactivation by overoxidation of 2-Cys peroxiredoxin (2-Cys Prx). Sensitivity to overoxidation depends on the structural GGLG and YF motifs present in eukaryotic 2-Cys Prxs and is believed to be absent from prokaryotic enzymes, thus representing a paradoxical gain of function exclusive to eukaryotic organisms. Here we show that 2-Cys Prxs from several prokaryotic organisms, including cyanobacteria, contain the GG(L/ V/I)G and YF motifs characteristic of sensitive enzymes. In search of the existence of overoxidation-sensitive 2-Cys Prxs in prokaryotes, we have analyzed the sensitivity to overoxidation of 2-Cys Prxs from two cyanobacterial strains, Anabaena sp. PCC7120 and Synechocystis sp. PCC6803. In vitro analysis of wild type and mutant variants of the Anabaena 2-Cys Prx showed that this enzyme is overoxidized at the peroxidatic cysteine residue, thus constituting an exception among prokaryotes. Moreover, the 2-Cys Prx from Anabaena is readily and reversibly overoxidized in vivo in response to high light and hydrogen peroxide, showing higher sensitivity to overoxidation than the Synechocystis enzyme. These cyanobacterial strains have different strategies to cope with hydrogen peroxide. While Synechocystis has low content of less sensitive 2-Cys Prx and high catalase activity, Anabaena contains abundant and sensitive 2-Cys Prx, but low catalase activity, which is remarkably similar to the chloroplast system. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc. Printed in the U.S.A.

Obregon S.,University of Seville | Caballero A.,University of Seville | Colon G.,University of Seville
Applied Catalysis B: Environmental | Year: 2012

BiVO 4 hierarchical heterostructures are synthesized by means of a surfactant free hydrothermal method having good photoactivities for the degradation of methylene blue under UV-vis irradiation. From the structural and morphological characterization it has been stated that BiVO 4 present the monoclinic crystalline phase with different morphologies depending on the pH value, type of precipitating agent and hydrothermal temperature and treatment time. The best photocatalytic performance was attained for the samples with needle-like morphology. © 2011 Elsevier B.V.

Murcia-Lopez S.,University of Seville | Hidalgo M.C.,University of Seville | Navio J.A.,University of Seville
Applied Catalysis A: General | Year: 2012

The photocatalytic activity, under sunlike illumination, for Rhodamine B (RhB) degradation using Bi 2WO 6-TiO 2 samples, is reported. Two different kinds of Bi 2WO 6-TiO 2 samples were studied, obtained by distinct methods: first, a mechanical mixing, by adding to synthesized nanosheet-like Bi 2WO 6 powder the corresponding amount of TiO 2 nanoparticles (P25) in order to obtain physical mixtures of both catalysts with different percentages of TiO 2 (5, 10 and 50 wt%); second, a single Bi 2WO 6-TiO 2 heterostructure was prepared by adding commercial TiO 2-P25 to the Bi 2WO 6 precursors (50 wt%) prior to the hydrothermal treatment, thus obtaining a sample with "in situ" TiO 2 incorporation. Comparisons between the photocatalytic behaviour of these samples and those exhibited by the single materials Bi 2WO 6 and TiO 2 (P25) were carried out, in order to establish the effect not only of the TiO 2 addition but also of the way in which TiO 2 (P25) is incorporated. The role of each single photocatalyst in the mixtures in the RhB degradation and mineralization under sunlike and just visible illumination was also studied. © 2011 Elsevier Ltd. All rights reserved.

Fiacchini M.,CNRS Laboratory for Analysis and Architecture of Systems | Alamo T.,University of Seville | Camacho E.F.,University of Seville
Automatica | Year: 2010

In this paper we provide a method to compute robust control invariant sets for nonlinear discrete-time systems. A simple criterion to evaluate if a convex set in state space is a robust control invariant set for a nonlinear uncertain system is presented. The criterion is employed to design an algorithm for computing a polytopic robust control invariant set. The method is based on the properties of DC functions, i.e. functions which can be expressed as the difference of two convex functions. Since the elements of a wide class of nonlinear functions have DC representation or, at least, admit an arbitrarily close approximation, the method is quite general. The algorithm requires relatively low computational resources. © 2010 Elsevier Ltd. All rights reserved.

Franco V.,University of Seville | Conde A.,University of Seville
International Journal of Refrigeration | Year: 2010

The detailed procedure for constructing the recently proposed phenomenological universal curve for the magnetic entropy change is presented, together with the exponents which control the field dependence of the different magnetocaloric-related magnitudes. Practical applications of the universal curve are also outlined: as a simple screening procedure of the performance of materials, as a method for making extrapolations to temperatures or fields not available in the laboratory, for the reduction of the experimental noise, for correcting the influence of non-saturating conditions, or as a way to eliminate the contribution of minority magnetic phases, among others. © 2009 Elsevier Ltd and IIR.

Marrero M.,University of Seville | Ramirez-De-Arellano A.,University of Seville
Construction Management and Economics | Year: 2010

During the last 25 years, a building cost system (BCS) has been developed in Andalusia, Spain. The first step was to generate the Andalusia construction information classification system (ACICS). Not only is ACICS valid as an estimation of cost, but it also provides a common method to manage information during the design and construction of buildings. Another important innovation is that this BCS defines the cost structure which distinguishes between direct and indirect cost and thereby allows a clear definition of all costs for each project type. Its most extended usage is for estimating cost in building projects and it is mandatory in public developments in Andalusia. This is the first time that this system is presented internationally and compared to others. Furthermore, the latest additions to ACICS are explained, and these take into account the waste management of reused and recycled materials in the budget estimate through a new division in the classification: Waste Management. Finally, a new way to address the cost related to construction and demolition waste management is explained which increases precision and generates an estimate independent from the general budget. © 2010 Taylor & Francis.

Luna R.,University of Seville | Rondon A.G.,University of Seville | Aguilera A.,University of Seville
Biochimica et Biophysica Acta - Gene Regulatory Mechanisms | Year: 2012

Coupling of transcription with mRNA processing and export has been shown to be relevant to efficient gene expression. A number of studies have determined that THO/TREX, a nuclear protein complex conserved from yeast to humans, plays an important role in mRNP biogenesis connecting transcription elongation, mRNA export and preventing genetic instability. Recent data indicates that THO could be relevant to different mRNA processing steps, including the 3'-end formation, transcript release and export. Novel connections of THO to proteins related to the splicing machinery, provide new views about possible functions of THO in mRNP biogenesis. In this review, we summarize the previous and new results concerning the impact of THO in transcription and its biological implications, with a special emphasis on the relationship with THSC/TREX-2 and other functionally related factors involved in mRNA biogenesis and export. The emerging picture presents THO as a dynamic complex interacting with the nascent RNA and with different factors connecting nuclear functions necessary for mRNP biogenesis with genome integrity, cellular homeostasis and development. This article is part of a Special Issue entitled: Nuclear Transport and RNA Processing. © 2012 Elsevier B.V.

Murcia J.J.,University of Seville | Navio J.A.,University of Seville | Hidalgo M.C.,University of Seville
Applied Catalysis B: Environmental | Year: 2012

The influence of Pt features, such as particle size, dispersion, oxidation state and amount of metal, on the improvement of the photoactivity of TiO 2 for phenol and methyl orange degradation was studied. The size of Pt deposits was precisely controlled by changing deposition time under medium light intensity during the photodeposition, with sizes ranging from 3 to 6. nm. Pt oxidation state was also strongly dependent on the photodeposition time. Photocatalytic activity results showed that the fraction of metallic platinum (Pt 0) was the crucial factor for the improvement of the activity. When the fraction of Pt 0 was similar, metal deposit size became the dominant parameter influencing the activity. The influence of the substrate to be degraded (phenol or methyl orange) was also studied. © 2012 Elsevier B.V.

Carnero A.,University of Seville
Biochimica et Biophysica Acta - Reviews on Cancer | Year: 2012

Reactive oxygen species, ROS, are beneficially involved in many signaling pathways that control development and maintain cellular homeostasis. In physiological conditions, a tightly regulated redox balance protects cells from injurious ROS activity, but if the balance is altered, it promotes various pathological conditions including cancer. Understanding the duality of ROS as cytotoxic molecules and key mediators in signaling cascades may provide novel opportunities for improved cancer therapy.MAP17 is a small 17-kDa non-glycosylated membrane protein that is overexpressed in many tumors of different origins, including carcinomas. Immunohistochemical analysis of MAP17 during cancer progression demonstrates that overexpression of the protein strongly correlates with the progression of most types of tumor. Tumor cells that overexpress MAP17 show an increased tumoral phenotype associated with an increase in ROS. However, in non-tumor cells MAP17 increases ROS, resulting in senescence or apoptosis. Therefore, in tumor cells, MAP17 could be a marker for increased oxidative stress and could define new therapeutic approaches. Here, we review the role of MAP17 as a putative oncogene, as well as its role in cancer and anticancer therapies. © 2012 Elsevier B.V.

Mateos-Naranjo E.,University of Seville | Andrades-Moreno L.,University of Seville | Redondo-Gomez S.,University of Seville
Bioresource Technology | Year: 2012

A glasshouse study concerning the halophyte Spartina densiflora was carried out to determine its tolerance and capacity to accumulate As. S. densiflora presented a high tolerance to As-induced stress, since all plants were able to survive at concentrations higher than 6.7mmoll -1As. However, As increment caused a reduction in S. densiflora growth, owing to a decrease in net photosynthetic rate. This reduction was prompted by the adverse effect on the photochemical apparatus and the reduction in the absorption of essential nutrients, which was linked with the reduction in G s, caused by the alteration of the K/Ca ratio, and with the reduction of photosynthetic pigment and Rubisco carboxilation. Arsenic tolerance was associated with the capacity to accumulate As in its roots (with values up to 2mgg -1) and largely avoid its transport to the leaves, this fact indicating that this species could be useful for arsenic phytostabilization purposes. © 2011 Elsevier Ltd.

Maria Cabeza J.,University of Seville | Acosta J.,University of Seville | Ales E.,University of Seville
Traffic | Year: 2010

Although endocytosis involves the fission pore, a transient structure that produces the scission between vesicle and plasma membranes, the dimensions and dynamics of fission pores remain unclear. Here we report that the pore resistance changes proceed in three distinct phases: an initial phase where the resistance increases at 31.7 ± 2.9 Gω/second, a slower linear phase with an overall slope of 11.7 ± 1.9 Gω/second and a final increase in resistance more steeply (1189 ± 136 Gω/second). The kinetics of these changes was calcium dependent. These sequential stages of the fission pore may be interpreted in terms of pore geometry as changes, first in pore diameter and then in pore length, according to which, before fission, the pore diameter consistently decreased to a value near 4 nm, whereas the pore length ranged between 20 and 300 nm. Dynamin, a mechanochemical GTPase, plays an important role in accelerating the fission event, preferentially in endocytotic vesicles of regular size, by increasing the rates of pore closure during the first and second phases of the fission pore, but hardly affected larger and longer-lived endocytotic events. These results suggest that fission pores are dynamic structures that form thin and long membrane necks regulated by intracellular calcium. Between calcium mediators, dynamin functions as a catalyst to increase the speed of single vesicle endocytosis. © 2010 John Wiley & Sons A/S.

Olmedo M.,University of Seville | Olmedo M.,University of Groningen | Ruger-Herreros C.,University of Seville | Corrochano L.M.,University of Seville
Genetics | Year: 2010

The development of asexual spores, that is, the process of conidiation, in the fungus Neurospora crassa is increased by light. The fluffy (fl) gene, encoding a major regulator of conidiation, is activated by light. We describe here a detailed characterization of the regulation by blue light of fl in vegetative hyphae. This induction requires the white collar complex (WCC) while the FLD protein acts as a dark repressor of fl transcription. We show that the WCC directly regulates fl transcription in response to blue light after transiently binding the promoter. We propose that fl is repressed by FLD in vegetative mycelia and that the repression is lost after light exposure and WCC activation. The increase in fl mRNA in vegetative mycelia after light exposure, and the corresponding increase in the amount of the regulatory FL protein, should promote the activation of the conidiation pathway. The activation by light of fl provides a simple mechanism for the activation of conidiation by blue light in Neurospora that may be at work in other fungi. Copyright © 2010 by the Genetics Society of America.

Gonzalez-Redondo P.,University of Seville
Poultry Science | Year: 2010

The effect of 0-, 7-, 14-, 21-, 28-, and 35-d storage periods on hatchability and weight loss during storage and incubation of red-legged partridge (Alectoris rufa) eggs stored at 15°C and 80% RH was studied. There was a significant effect of storage period on egg weight loss during storage (P < 0.001), a significant increase occurring in weight loss for each additional week the eggs were stored, and this weight loss amounted to more than 3% for the eggs stored for 35 d. Storage period affected egg weight loss during incubation (P < 0.05). An increase in egg weight loss during incubation occurred, increasing from 21 d of storage and amounting to more than 10% for the eggs stored for 35 d. Storage period had a significant effect on hatchability (P < 0.05). Storage of red-legged partridge eggs up to 28 d does not affect subsequent hatchability, but a significant decline in hatchability occurs when the eggs are stored for 35 d. This research confirms, as occurs in other Alectoris species, that long-term storage of redlegged partridge eggs (to 28 d) does not have a negative effect on hatchability. These findings will be useful in terms of successful hatchery management, mainly by allowing prolonged storage of eggs while gathering a sufficient-sized batch to be incubated, and shipment of long shelf life hatching eggs at game farms while losing little hatchability until further incubation. © 2010 Poultry Science Association Inc.

Gonzalez-Delacruz V.M.,University of Seville | Pereniguez R.,University of Seville | Ternero F.,University of Seville | Holgado J.P.,University of Seville | Caballero A.,University of Seville
ACS Catalysis | Year: 2011

The effect of a reduction process with CO or H2 on the size of nickel particles in Ni/ZrO2 dry methane reforming catalysts have been studied by means of in situ X-ray Absorption Spectroscopy (XAS) and Diffuse Reflectance FTIR Spectroscopy (DRIFTS). Our results clearly indicate that a high temperature treatment with CO increases the dispersion of the nickel metallic phase. XAS results have shown a lower coordination number of Ni in the sample treated with CO than that reduced with H2. From the DRIFTS results, it can be established that, under the CO treatment, the formation of Ni(CO) 4 complexes corrodes the nickel particles, decreasing their size. The formation of these gas molecules occurs without measurable losses of nickel from the catalyst which maintains the same nickel content after the hydrogen or the CO treatment at high temperature. Therefore, this airborne nickel compound, by colliding with the zirconia surface, must deposit the nickel metal atoms around onto the support. This behavior is evidence of an important interaction between nickel and zirconia surface as unlike other supports there is no losses of nickel during the dispersion process on zirconia. Although different effects of CO on nickel catalysts have been previously described, we have found for the first time several experimental evidences demonstrating the whole redispersion phenomenon. © 2011 American Chemical Society.

Ventosa A.,University of Seville | de la Haba R.R.,University of Connecticut | Sanchez-Porro C.,University of Seville | Papke R.T.,University of Connecticut
Current Opinion in Microbiology | Year: 2015

Recent studies based on metagenomics and other molecular techniques have permitted a detailed knowledge of the microbial diversity and metabolic activities of microorganisms in hypersaline environments. The current accepted model of community structure in hypersaline environments is that the square archaeon Haloquadratum waslbyi, the bacteroidete Salinibacter ruber and nanohaloarchaea are predominant members at higher salt concentrations, while more diverse archaeal and bacterial taxa are observed in habitats with intermediate salinities. Additionally, metagenomic studies may provide insight into the isolation and characterization of the principal microbes in these habitats, such as the recently described gammaproteobacterium Spiribacter salinus. © 2015 Elsevier Ltd.

Talkner P.,University of Augsburg | Morillo M.,University of Seville | Yi J.,Pusan National University | Hanggi P.,University of Augsburg
New Journal of Physics | Year: 2013

Work performed on a system in a microcanonical state by changes in a control parameter is characterized in terms of its statistics. The transition probabilities between eigenstates of the system Hamiltonians at the beginning and the end of the parameter change obey a detailed balance-like relation from which various forms of the microcanonical fluctuation theorem are obtained. As an example, sudden deformations of a two-dimensional harmonic oscillator potential are considered, and the validity of the microcanonical Jarzynski equality connecting the degrees of degeneracy of energy eigenvalues before and after the control parameter change is confirmed. © IOP Publishing and Deutsche Physikalische Gesellschaft.

Laguna O.H.,University of Seville | Centeno M.A.,University of Seville | Boutonnet M.,KTH Royal Institute of Technology | Odriozola J.A.,University of Seville
Applied Catalysis B: Environmental | Year: 2011

A series of Ce-Fe mixed oxides as well as the pure oxides were synthesized by the microemulsions method. The solid solution formation was established for all the Fe-doped systems and only a hardly noticeable segregation of α-Fe2O3 was appreciated for the solid with the maximum iron content (50at.% Fe). The oxygen exchange is improved for all the Fe-doped systems; however the 10at.% Fe appears as the optimal iron content for achieving the maximum oxygen vacancies concentration and the higher reducibility efficiency. The CO oxidation (TOX, PROX) is especially achieved for the solids with the lower iron contents but with a superior oxygen vacancies proportion. These Ce-Fe systems prepared from microemulsions are very attractive to be considered as supports for depositing active phases capable of enhancing oxygen exchange ability of the whole system, allowing higher CO oxidation abilities. © 2011 Elsevier B.V.

Murcia-Lopez S.,University of Seville | Hidalgo M.C.,University of Seville | Navio J.A.,University of Seville
Applied Catalysis A: General | Year: 2011

A series of Bi3+-doped TiO2 catalysts with a doping concentration up to 2 wt% were prepared by a sol-gel hydrothermal method. The prepared photocatalysts were characterized by different techniques to determine their structure, morphology and light absorption properties. The activities were evaluated in the photocatalytic oxidation of phenol in aqueous solution under UV-vis illumination. The experimental results indicate that the presence of Bi3+ in TiO2 catalysts enhances the photocatalytic reaction of phenol degradation, although the efficiency of the process markedly depends on the nominal content of the Bi3+ and on the calcination temperature. It was found that the optimal dosage of 0.5 wt% Bi3+ in TiO2 and calcinations at 600 °C 4 h achieved the fastest reaction of phenol degradation under the experimental conditions. From the comparison of the initial rates of the photocatalytic degradation of phenol between home prepared undoped and Bi3+-doped TiO2 with commercial TiO2 Degussa P25, it can be inferred that home prepared TiO 2 calcined at temperatures above 500 °C clearly exceed the photocatalytic performance of P25. When bismuth is incorporated, the reaction rate values are even higher, especially at 600 °C. Even when Bi 3+-doped TiO2 (0.5 wt% Bi3+) calcined at 600 °C has almost the same BET surface than P25, its activity is better. In particular, the reaction rate for the sample with a 0.5% mass content of Bi 3+ calcined at 600 °C not only present higher value with respect to the other series but also a degree of mineralization close to 100%. © 2011 Elsevier B.V. All rights reserved.

Tavares E.,University of Seville | Minano F.J.,University of Seville
Clinical Science | Year: 2010

Severe sepsis and septic shock are an important cause of mortality and morbidity. These illnesses can be triggered by the bacterial endotoxin LPS (lipopolysaccharide) and proinflammatory cytokines, particularly TNF-α (tumour necrosis factor-α) and IL (interleukin)-1β. Severity and mortality of sepsis have also been associated with high concentrations of N-PCT (aminoprocalcitonin), a 57-amino-acid neuroendocrine peptide derived from ProCT (procalcitonin). Previous studies in a lethal model of porcine polymicrobial sepsis have revealed that immunoneutralization with IgG that is reactive to porcine N-PCT significantly improves shortterm survival. To explore further the pathophysiological role of N-PCT in sepsis, we developed an antibody raised against a highly conserved amino acid sequence of humanN-PCT [N-PCT-(44-57)]. This sequence differs by only one amino acid from ratN-PCT. First, we demonstrated the specificity of this antibody in a well-proven model of anorexia induced in rats by central administration of human N-PCT-(1-57). Next we explored further the therapeutic potential of anti-N-PCT-(44-57) in a rat model of lethal endotoxaemia and determined how this immunoneutralization affected LPS-induced lethality and cytokine production. We show that this specific antibody inhibited the LPS-induced early release of TNF-α and IL-1β and increased survival, even if treatment began after the cytokine response had occurred. In addition, anti-N-PCT-(44-57) may increase longterm survival in LPS-treated rats by up-regulating the late production of counter-regulatory antiinflammatory mediators such as ACTH (adrenocorticotropic hormone) and IL-10. In conclusion, these results support N-PCT as a pro-inflammatory factor in both the early and the late stages of lethal endotoxaemia, and suggest anti-N-PCT as a candidate for septic shock therapy. © The Authors Journal compilation © 2010 Biochemical Society.

Gonzalez-Varo J.P.,University of Seville | Traveset A.,CSIC - Mediterranean Institute for Advanced Studies
Annals of Botany | Year: 2010

Background and Aims: Variation in inbreeding depression (δ) among individual plants is considered to play a central role in mating system evolution and population genetics. Moreover, such variation could be linked to individual susceptibility to pollen limitation (PL) because those individuals strongly affected by δ for seed production will require more outcross pollen for setting a given number of fruits or seeds. However, no study has tested explicitly for associations between PL and δ at the individual plant level. This study assesses the extent of among-individual variation in PL and δ, the consistency of δ across life stages, and the relationships between individual PL and δ in the mixed-mating shrub Myrtus communis. Methods Controlled hand-pollinations were performed in a natural M. communis population. Marked flowers were monitored until fruit production and a greenhouse experiment was conducted with the seeds produced.Key Results Compared with selfing, outcross-pollination enhanced seed number per fruit, germination rate and seedling growth, but did not enhance fruit-set. Only seed number per fruit was pollen limited and, thus, cumulative pollen limitation depended more on pollen quality (outcross pollen) than on quantity. The effects of δ varied considerably across life stages and individual plants. Cumulative δ was high across individuals (mean δ = 0·65), although there were no positive correlations between δ values at different life stages. Interestingly, maternal plants showing stronger δ for seed production were more pollen limited, but they were also less affected by δ for seedling growth because of a seed size/number trade-off. Conclusions Results show a general inconsistency in δ across life stages and individuals, suggesting that different deleterious loci are acting at different stages. The association between δ and PL at the individual level corroborates the idea that pollen limitation may be 'genotype-dependent' regardless of other factors. © The Author 2010. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.

Aguilera A.,University of Seville | Gaillard H.,University of Seville
Cold Spring Harbor Perspectives in Biology | Year: 2014

A particularly relevant phenomenon in cell physiology and proliferation is the fact that spontaneous mitotic recombination is strongly enhanced by transcription. The most accepted view is that transcription increases the occurrence of double-strand breaks and/or singlestranded DNA gaps that are repaired by recombination. Most breaks would arise as a consequence of the impact that transcription has on replication fork progression, provoking its stalling and/or breakage. Here, we discuss the mechanisms responsible for the cross talk between transcription and recombination, with emphasis on (1) the transcription-replication conflicts as the main source of recombinogenic DNA breaks, and (2) the formation of cotranscriptional R-loops as a major cause of such breaks. The new emerging questions and perspectives are discussed on the basis of the interference between transcription and replication, as well as the way RNA influences genome dynamics. © 2014 Cold Spring Harbor Laboratory Press; all rights reserved.

Fernandez-Pevida A.,University of Seville | Kressler D.,University of Fribourg | de la Cruz J.,University of Seville
Wiley Interdisciplinary Reviews: RNA | Year: 2015

Most, if not all RNAs, are transcribed as precursors that require processing to gain functionality. Ribosomal RNAs (rRNA) from all organisms undergo both exo- and endonucleolytic processing. Also, in all organisms, rRNA processing occurs inside large preribosomal particles and is coupled to nucleotide modification, folding of the precursor rRNA (pre-rRNA), and assembly of the ribosomal proteins (r-proteins). In this review, we focus on the processing pathway of pre-rRNAs of cytoplasmic ribosomes in the yeast Saccharomyces cerevisiae, without doubt, the organism where this pathway is best characterized. We summarize the current understanding of the rRNA maturation process, particularly focusing on the pre-rRNA processing sites, the enzymes responsible for the cleavage or trimming reactions and the different mechanisms that monitor and regulate the pathway. Strikingly, the overall order of the various processing steps is reasonably well conserved in eukaryotes, perhaps reflecting common principles for orchestrating the concomitant events of pre-rRNA processing and ribosome assembly. © 2014 John Wiley & Sons, Ltd.

Arzac G.M.,University of Seville | Rojas T.C.,University of Seville | Fernandez A.,University of Seville
Applied Catalysis B: Environmental | Year: 2012

Catalysed sodium borohydride hydrolysis is a high-potential method to produce hydrogen for portable applications. Co-B catalysts are the most chosen because they are easily prepared, cheap and efficient. The addition of small amounts of Ru produces a significant enhancement in catalytic activity. In the present work a series of Co-Ru-B catalysts with variable Ru content was prepared, isolated and characterized. The comprehension of the synergistic effect was achieved trough the incorporation of the nanostructural dimension to the study of surface and bulk chemical states of the involved atoms along the series. It was found that up to 70% (of total metal) atomic content of Ru the catalysts can be considered isostructural to the single Co-B catalyst in the nanoscale. A structural transition occurs in the case of the pure Ru-B material to produce a boron deficient material with higher nanoparticle size. This structural transition together with Co segregation and Ru dispersion play a key role when explaining a [OH-] dependent effect. The inexistence of borate layers in Ru rich catalysts is suggestive in the research for non deactivating catalysts. © 2012 Elsevier B.V.

Vazquez R.,University of Seville | Krstic M.,University of California at San Diego
IEEE Transactions on Control Systems Technology | Year: 2010

In this paper, we consider a 2-D model of thermal fluid convection that exhibits the prototypical Rayleigh-Bernard convective instability. The fluid is enclosed between two cylinders, heated from above, and cooled from below, which makes its motion unstable for a large enough Rayleigh number. We design an stabilizing output feedback boundary control law for a realistic collocated setup, with actuation and measurements located at the outer boundary. Actuation is through rotation (direct velocity actuation) and heat flux (heating or cooling) of the outer cylinder, while measurements of friction and temperature are obtained at the same boundary. Though only a linearized version of the plant is considered in the design, an extensive closed loop simulation study of the nonlinear model shows that our design works for reasonably large initial conditions. A highly accurate approximation to the control kernels and observer output injection gains is found in closed form. © 2009 IEEE.

Liu J.,University of California at Los Angeles | Munoz de la Pena D.,University of Seville | Christofides P.D.,University of California at Los Angeles
Automatica | Year: 2010

In this work, we design distributed Lyapunov-based model predictive controllers for nonlinear systems that coordinate their actions and take asynchronous measurements and delays explicitly into account. Sufficient conditions under which the proposed distributed control designs guarantee that the state of the closed-loop system is ultimately bounded in a region that contains the origin are provided. The theoretical results are demonstrated through a chemical process example. © 2009 Elsevier Ltd. All rights reserved.

Raffo G.V.,University of Seville | Ortega M.G.,University of Seville | Rubio F.R.,University of Seville
Automatica | Year: 2010

This paper presents an integral predictive and nonlinear robust control strategy to solve the path following problem for a quadrotor helicopter. The dynamic motion equations are obtained by the Lagrange-Euler formalism. The proposed control structure is a hierarchical scheme consisting of a model predictive controller (mpc) to track the reference trajectory together with a nonlinear H∞ controller to stabilize the rotational movements. In both controllers the integral of the position error is considered, allowing the achievement of a null steady-state error when sustained disturbances are acting on the system. Simulation results in the presence of aerodynamic disturbances, parametric and structural uncertainties are presented to corroborate the effectiveness and the robustness of the proposed strategy. © 2009 Elsevier Ltd. All rights reserved.

Calero N.,University of Seville | Munoz J.,University of Seville | Cox P.W.,University of Birmingham | Heuer A.,University of Birmingham | Guerrero A.,University of Seville
Food Hydrocolloids | Year: 2013

Relatively concentrated (40 wt%) O/W emulsions formulated with high-oleic sunflower oil as disperse phase, potato protein isolate as emulsifier and chitosan as stabiliser were prepared by rotor-stator/high-pressure valve/rotor-stator homogenization. The influence of chitosan concentration on the physical stability of emulsions was studied in (0.25-1) wt% range by visual inspection, rheological and microstructural techniques. Steady shear flow curves were sensitive to the occurrence of creaming upon the rise of zero-shear viscosity values. The effect of increasing concentration of chitosan on the zero-shear viscosity turned out to be dependent on emulsion ageing and always resulted in a stepwise increase of the critical shear rate for the onset of shear thinning flow. The critical oscillatory shear stress for the onset of non-linear viscoelastic behaviour was more sensitive than the critical shear rate to detect creaming in emulsions. Mechanical spectra are definitely demonstrated to be the most powerful tool to detect not only creaming but also oil droplet flocculation on account of changes in the plateau relaxation zone. CSLM micrographs supported the interpretation of dynamic viscoelastic results, especially when flocculation as well as coalescence took place. Cryo-SEM micrographs evidenced the formation of increasingly denser protein-polysaccharide networks with chitosan concentration and the fact that the latter governs the microstructure of the emulsion when reaches 1 wt% concentration promoting enhanced physical stability. © 2012 Elsevier Ltd.

Cardenal-Munoz E.,University of Seville | Ramos-Morales F.,University of Seville
Journal of Bacteriology | Year: 2013

SteA is a protein that can be translocated into host cells through the two virulence-related type III secretion systems that are present in Salmonella enterica. We used the T-POP system to carry out general screens for loci that exhibited activation or repression of a steA::lacZ fusion. These screens identified the histidine kinase PhoQ and the responseregulator PhoP as positive regulators of steA. Transcription of this gene is σ70 dependent, and the promoter of steA contains a PhoP-binding site that mediates direct regulation by PhoP. Our screens also detected MgrB (also known as YobG) as a negative regulator of the expression of steA. Disruption of the gene encoding the periplasmic disulfide oxidoreductase DsbA or addition of the reducing agent dithiothreitol increases transcription of steA. The effects of MgrB and DsbA on steA are mediated by PhoP. These results suggest that the cellular redox status is a factor contributing to regulation of steA and, probably, other virulence genes regulated by the PhoQ/PhoP two-component system. © 2013, American Society for Microbiology.

Obregon S.,University of Seville | Kubacka A.,CSIC - Institute of Catalysis | Fernandez-Garcia M.,CSIC - Institute of Catalysis | Colon G.,University of Seville
Journal of Catalysis | Year: 2013

Erbium-doped TiO2 materials are synthesized by means of a surfactant-free hydrothermal method having good photoactivities for the liquid-phase degradation of phenol and MB and the gas phase of toluene. From the structural and morphological characterization, it has been stated that the presence of Er3+ induces a progressive anatase cell expansion due to its incorporation in the TiO2 lattice. The best photocatalytic performance was attained for the samples with 2 at% of Er3+ irrespective of the chemical degradation reaction essayed. From activity and optical studies under different irradiation excitation conditions, a dual-type mechanism is proposed to be at the origin of the photocatalytic activity enhancement. On one hand, the improvement observed under UV irradiation occurs by the effective charge separation promoted by Er3+ species which would act as electron scavenger. Besides, the up-conversion luminescence process of Er3+ allows profiting the NIR range of the lamp and transferring energy in the UV range to the TiO2. The dual action of Er ions located at anatase networks will open up a wide roadway for the developing of an integral solar active photocatalyst. © 2012 Elsevier Inc. All rights reserved.

Valverde J.M.,University of Seville
Chemical Engineering Journal | Year: 2013

The CaO conversion of CO2 sorbents subjected to repeated series of carbonation/calcination cycles is investigated as affected by thermal pretreatment. The behavior of nonpretreated sorbents is characterized by the progressive sintering of the initial CaO skeleton derived from a quick preheating of its precursor. As a consequence, CaO conversion suffers a drastic decrease in the first cycles and gradually converges towards a residual value. The evolution of conversion in the first cycles for pretreated sorbents is determined by a diverse mechanism, which is mainly characterized by the growth of a renewed soft skeleton due to promoted solid-state diffusive carbonation, which leads to an increase of conversion with the cycle number up to a maximum value. A mathematical model is proposed based on the balance between the surface area loss due to sintering in the calcination stage of each cycle and the surface area gain due to regeneration of the skeleton. A key feature to describe self-reactivation is that renovation of the soft skeleton becomes progressively less efficient as the number of cycles builds up. An extensive series of data reported in the literature has been analyzed in the light of the proposed model, which has served to quantify the level of self-reactivation as affected by a wide variety of experimental conditions such as preheating temperature and duration, hydration, calcination under a CO2 enriched atmosphere, grinding, addition of thermally stable dopants, and presence of foreign ions in the limestone. © 2013 Elsevier B.V.

Romero L.C.,University of Seville | Aroca M.A.,University of Seville | Laureano-Marin A.M.,University of Seville | Moreno I.,University of Seville | And 2 more authors.
Molecular Plant | Year: 2014

Cysteine occupies a central position in plant metabolism because it is a reduced sulfur donor molecule involved in the synthesis of essential biomolecules and defense compounds. Moreover, cysteine per se and its derivative molecules play roles in the redox signaling of processes occurring in various cellular compartments. Cysteine is synthesized during the sulfate assimilation pathway via the incorporation of sulfide to O-acetylserine, catalyzed by O-acetylserine(thiol)lyase (OASTL). Plant cells contain OASTLs in the mitochondria, chloroplasts, and cytosol, resulting in a complex array of isoforms and subcellular cysteine pools. In recent years, significant progress has been made in Arabidopsis, in determining the specific roles of the OASTLs and the metabolites produced by them. Thus, the discovery of novel enzymatic activities of the less-abundant, like DES1 with L-cysteine desulfhydrase activity and SCS with S-sulfocysteine synthase activity, has provided new perspectives on their roles, besides their metabolic functions. Thereby, the research has been demonstrated that cytosolic sulfide and chloroplastic S-sulfocysteine act as signaling molecules regulating autophagy and protecting the photosystems, respectively. In the cytosol, cysteine plays an essential role in plant immunity; in the mitochondria, this molecule plays a central role in the detoxification of cyanide, which is essential for root hair development and plant responses to pathogens. © 2013 © The Author 2013. Published by the Molecular Plant Shanghai Editorial Office in association with Oxford University Press on behalf of CSPB and IPPE, SIBS, CAS.

Abril Hernandez J.-M.,University of Seville
Journal of Environmental Radioactivity | Year: 2016

Unsupported 210Pb (210Pbexc) vs. mass depth profiles do not contain enough information as to extract a unique chronology when both, 210Pbexc fluxes and mass sediment accumulation rates (SAR) independently vary with time. Restrictive assumptions are needed to develop a suitable dating tool. A statistical correlation between fluxes and SAR seems to be a quite general rule. This paper builds up a new 210Pb-based dating tool by using such a statistical correlation. It operates with SAR and initial activities that closely follow normal distributions, what leads to the expected correlation between fluxes and SAR. An intelligent algorithm solves their best arrangement downcore to fit the experimental 210Pbexc vs. mass depth profile, generating then solutions for the chronological line, and for the histories of SAR and fluxes. Parametric maps of a χ-function serve to find out the solution and to support error estimates. Optionally, the model's answers can be better constrained through the use of time markers. The performance of the model is illustrated with a synthetic core, and with real cases using published data for varved sediment cores. © 2015 Elsevier Ltd.

Lopez-Garrido J.,University of Seville | Casadesus J.,University of Seville
Genetics | Year: 2010

DNA adenine methylase (Dam-) mutants of Salmonella enterica are attenuated in the mouse model and present multiple virulence-related defects. Impaired interaction of Salmonella Dam- mutants with the intestinal epithelium has been tentatively correlated with reduced secretion of pathogenicity island 1 (SPI-1) effectors. In this study, we show that S. enterica Dam- mutants contain lowered levels of the SPI-1 transcriptional regulators HilA, HilC, HilD, and InvF. Epistasis analysis indicates that Dam-dependent regulation of SPI-1 requires HilD, while HilA, HilC, and InvF are dispensable. A transcriptional hilD::lac fusion is expressed at similar levels in Dam+ and Dam- hosts. However, lower levels of hilD mRNA are found in a Dam- background, thus providing unsuspected evidence that Dam methylation might exert post-transcriptional regulation of hilD expression. This hypothesis is supported by the following lines of evidence: (i) lowered levels of hilD mRNA are found in Salmonella Dam- mutants when hilD is transcribed from a heterologous promoter; (ii) increased hilD mRNA turnover is observed in Dam- mutants; (iii) lack of the Hfq RNA chaperone enhances hilD mRNA instability in Dam- mutants; and (iv) lack of the RNA degradosome components polynucleotide phosphorylase and ribonuclease E suppresses hilD mRNA instability in a Dam - background. Our report of Dam-dependent control of hilD mRNA stability suggests that DNA adenine methylation plays hitherto unknown roles in post-transcriptional control of gene expression. Copyright © 2010 by the Genetics Society of America.

Sanchez-Jimenez P.E.,University of Seville | Valverde J.M.,University of Seville | Perez-Maqueda L.A.,University of Seville
Fuel | Year: 2014

Limestone derived CaO conversion when subjected to multiple carbonation/calcination cycles is a subject of interest currently fueled by several industrial applications of the so-called Ca-looping (CaL) technology. The multicyclic CaO conversion at Ca-looping conditions exhibits two main features as demonstrated by thermogravimetric analysis (TGA). On one hand, carbonation occurs by two well differentiated phases: a first kinetically-driven fast phase and a subsequent much slower solid-state diffusion controlled phase. On the other, carbonation in the fast phase usually shows a drastic decay with the cycle number along the first carbonation/calcination cycles. This trend can be reversed by means of heat pretreatment, which induces a marked loss of fast conversion in the first carbonation but enhances diffusion of CO2 in the solid. Upon decarbonation the regenerated CaO skeleton displays an increased conversion in the fast carbonation phase of the next cycle, a phenomenon which has been referred to as reactivation. Nonetheless, sorbent reactivation is hampered by looping carbonation/calcination conditions as those to be likely found in practice such as carbonation stages characterized by low CO2 concentrations and short duration and calcination stages at high temperatures in a CO2 enriched atmosphere, which causes a sintering and loss of activity of the regenerated CaO skeleton. We analyze in this work sorbent reactivation as affected by heat pretreatment and carbonation/calcination conditions. Aimed at shedding light on the role played by these conditions on reactivation we look separately at the multicyclic evolution of conversion in the kinetic and diffusive phases. Generally, the evolution of multicyclic conversion after the first cycle can be described by a balance between the surface area gain due to diffusive carbonation and the surface area loss as caused by sintering in the calcination stage. A significant gain of relative surface area after the first cycle, which is favored by harshening the heat pretreatment conditions, leads however to a marked decay of it during subsequent cycles, which precludes reactivation for an extended interval of cycles. On the other hand, sorbent grinding, if performed before heat pretreatment, leads to a less marked but more sustainable reactivation along the cycles. A novel observation reported in our work is that pretreatment of limestone in a CO 2 atmosphere leads upon a subsequent quick decarbonation to a CaO skeleton with extraordinarily enhanced reactivity in the kinetically-driven carbonation phase and with a high resistance to solid-state diffusion, which can be attributed to annealing of the crystal structure as reported by independent studies. ©2013 Elsevier Ltd. All rights reserved.

Valverde J.M.,University of Seville | Sanchez-Jimenez P.E.,University of Seville | Perez-Maqueda L.A.,University of Seville
Fuel | Year: 2014

The Ca-looping (CaL) process, based on the multicyclic carbonation/ calcination of limestone derived CaO, has emerged recently as a potentially economically advantageous technology to achieve sustainable postcombustion and precombustion CO2 capture efficiencies. Yet, a drawback that hinders the efficiency of the CaL process is the drastic drop of limestone capture capacity as the number of carbonation/calcination cycles is increased. Precalcination of limestone at high temperatures for a prolonged period of time has been proposed as a potential technique to reactivate the sorbent, which is however precluded by regeneration temperatures above 850 C and low CO2 concentrations in the carbonator to be found in the practical situation. Under these conditions, heat pretreatment leads to a stable yet very small CaO conversion. On the other hand, the introduction of a recarbonation stage between the ordinary carbonation and calcination stages has been shown to decelerate the rate of sorbent activity decay even though this favorable effect is not noticeable up to a number of above 10-15 cycles. The present manuscript demonstrates that the synergetic action of heat pretreatment and recarbonation yields a high and stable value for the multicyclic conversion of limestone derived CaO. It is foreseen that recarbonation of heat pretreated limestone would lead to a reduction of process costs especially in the case of precombustion applications. Even though sorbent purging will always be needed because of ash accumulation and sulphation in postcombustion CO2 capture applications, the stable and high multicyclic CaO conversion achieved by the combination of these techniques would make it necessary to a lesser extent. © 2014 Elsevier Ltd. All rights reserved.

Sanchez-Jimenez P.E.,University of Seville | Perez-Maqueda L.A.,University of Seville | Valverde J.M.,University of Seville
Applied Energy | Year: 2014

This work presents a CO2 sorbent that may be synthesized from low-cost and widely available materials following a simple method basically consisting of impregnation of a nanostructured silica support with a saturated solution of calcium nitrate. In a first impregnation stage, the use of a stoichiometric CaO/SiO2 ratio serves to produce a calcium silicate matrix after calcination. This calcium silicate matrix acts as a thermally stable and mechanically hard support for CaO deposited on it by further impregnation. The CaO-impregnated sorbent exhibits a stable CaO conversion at Ca-looping conditions whose value depends on the CaO wt% deposited on the calcium silicate matrix, which can be increased by successive reimpregnations. A 10wt% CaO impregnated sorbent reaches a stable conversion above 0.6 whereas the stable conversion of a 30wt% CaO impregnated sorbent is around 0.3, which is much larger than the residual conversion of CaO derived from natural limestone (between 0.07 and 0.08). Moreover, particle size distribution measurements of samples predispersed in a liquid and subjected to high energy ultrasonic waves indicate that the CaO-impregnated sorbent has a relatively high mechanical strength as compared to limestone derived CaO. © 2013 Elsevier Ltd.

Valverde J.M.,University of Seville | Sanchez-Jimenez P.E.,University of Seville | Perez-Maqueda L.A.,University of Seville
Energy and Fuels | Year: 2014

Even though an increasing number of pilot-scale plants are demonstrating the potential efficiency of the Ca-looping technology to capture CO2 at a commercial level, a still standing matter of concern is the loss of carbonation reactivity of the regenerated CaO by calcination, which is expected to be particularly marked at realistic conditions necessarily implying a high CO2 partial pressure in the calciner. In this work, we address the effect of previously reported strategies for sorbent reactivation, namely heat pretreatment and the introduction of a recarbonation stage before regeneration. Both techniques, either combined or separately, are shown to favor the carbonation reactivity, albeit CaO regeneration is usually carried out at low CO2 partial pressure in lab-scale tests. Novel results reported in this paper show the opposite when the sorbent is regenerated by calcination at high CO2 concentration, which is arguably due to the diverse mechanisms that rule decarbonation depending on the CO2 concentration in the calciner atmosphere. Dynamic and reversible adsorption/desorption of CO2 is thought to govern decarbonation during calcination at high CO2 partial pressure, which would be hindered by the introduction of a recarbonation stage before carbonation. Moreover, carbonation in the fast phase is severely hampered as a result of the marked loss of reactivity of the surface of CaO regenerated under high CO2 partial pressure. On the other hand, heat pretreatment and harsh calcination conditions lead to a notable enhancement of diffusion, which would favor the process efficiency. In these conditions, diffusion controlled carbonation becomes a significant contribution to CaO conversion, which is notably increased by prolonging the carbonation stage. Heat pretreatment allows also reducing the calcination temperature at high CO2 partial pressure while still achieving full decarbonation in short residence times. © 2014 American Chemical Society.

Valverde J.M.,University of Seville | Sanchez-Jimenez P.E.,University of Seville | Perez-Maqueda L.A.,University of Seville
Applied Energy | Year: 2014

The multicyclic carbonation/calcination (c/c) of CaO solid particles at high temperature is at the basis of the recently emerged Calcium-looping (CaL) technology, which has been shown to be potentially suitable for achieving high and sustainable post-combustion CO2 capture efficiency. Despite the success of pilot plant projects at the MWth scale, a matter of concern for scaling-up the CaL technology to a commercial level (to the GWth scale) is that the CaO carbonation reactivity can be recovered only partially when the sorbent is regenerated by calcination at high temperatures (around 950°C) as required by the CO2 high concentration in the calciner. In order to reactivate the sorbent, a novel CaL concept has been proposed wherein a recarbonator reactor operated at high temperature/high CO2 concentration leads to further carbonation of the solids before entering into the calciner for regeneration. Multicyclic thermogravimetric analysis (TGA) tests demonstrate the feasibility of recarbonation to reactivate the sorbent regenerated at high calcination temperatures yet at unrealistically low CO2 partial pressure mainly because of technical limitations concerning low heating/cooling rates. We report results from multicyclic c/c and carbonation/recarbonation/calcination (c/r/c) TGA tests at high heating/coling rates and in which the sorbent is regenerated in a dry atmosphere at high CO2 partial pressure. It is shown that at these conditions there is a drastic drop of CaO conversion to a very small residual value in just a few cycles. Moreover, the introduction of a recarbonation stage has actually an adverse effect. Arguably, CaCO3 decomposition in a CO2 rich atmosphere is ruled by CO2 dynamic adsorption/desorption in reactive CaO (111) surfaces as suggested by theoretical studies, which would preclude the growth of the regenerated CaO crystal structure along these reactive surfaces, and this effect would be intensified by recarbonation. Nevertheless, the presence of H2O in the calciner, which is also adsorbed/desorbed dynamically in CaO reactive planes, would shield CO2 adsorption/desorption thus mitigating the deeply detrimental effect of CO2 on the carbonation reactivity of the regenerated CaO structure. Oxy-combustion, which produces a significant amount of H2O, is currently used in pilot-scale plants to raise the temperature in the calciner. Auxiliary techniques are being explored to help heating the partially carbonated solids since oxyxombustion represents an important penalty to the CaL technology. Our study suggests that steam injection would be necessary in a dry calciner environment to avoid a sharp loss of CaO conversion if the sorbent is regenerated at high CO2 partial pressure. © 2014 Elsevier Ltd.

Leckner B.,Chalmers University of Technology | Gomez-Barea A.,University of Seville
Applied Energy | Year: 2014

The conditions for CO2 reduction in a circulating fluidized bed (CFB) oxy-boiler are studied, that is, operation with pure oxygen, diluted by recirculated flue gases to moderate the combustion process. Two cases are analyzed: the ready-to-convert case, a normal air-fired CFB boiler, only slightly modified to be operated with oxygen instead of air for CO2 capture, and a more general option, an entirely new design, employing high oxygen concentration in the input to the oxy-fuel CFB boiler. It is found that at a given fuel load, the relevant parameters for maintaining the CFB performance (bed temperature and fluidization velocity) in the ready-to-convert case cannot be kept entirely equal to those in the air-fired case, and some compromise has to be found. The new-design case results in a smaller boiler than that of the comparable air-fired case, depending on the oxygen concentration and the corresponding flue-gas recirculation. This case is expected to contribute favorably to reduction of the cost of CO2 removal. © 2014 Elsevier Ltd.

Galbis J.A.,University of Seville | Garcia-Martin M.G.,University of Seville
Topics in Current Chemistry | Year: 2010

The low degradability of petroleum-based polymers and the massive use of these materials constitute a serious problem because of the environmental pollution that they can cause. Thus, sustained efforts have been extensively devoted to produce new polymers based on natural renewing resources and with higher degradability. Of the different natural sources, carbohydrates stand out as highly convenient raw materials because they are inexpensive, readily available, and provide great stereochemical diversity. New polymers, analogous to the more accredited technical polymers, but based on chiral monomers, have been synthesized from natural and available sugars. This chapter describes the potential of sugar-based monomers as precursors to a wide variety of macromolecular materials. © 2010 Springer-Verlag Berlin Heidelberg.

Queralto R.,University of Seville
Science and Engineering Ethics | Year: 2013

This article explores the transformation of ethics in a globalizing technological society. After describing some basic features of this society, particularly the primacy it gives to a special type of technical rationality, three specific influences on traditional ethics are examined: (1) a change concerning the notion of value, (2) the decreasing relevance of the concept of axiological hierarchy, and (3) the new internal architecture of ethics as a net of values. These three characteristics suggest a new pragmatic understanding of ethics. From a pragmatic perspective, the process of introducing ethical values into contemporary society can be regarded as a beneficial Trojan horse, a metaphor that will be developed further. © 2011 Springer Science+Business Media B.V.

Conejero S.,University of Seville | Paneque M.,University of Seville | Poveda M.L.,University of Seville | Santos L.L.,University of Seville | Carmona E.,University of Seville
Accounts of Chemical Research | Year: 2010

Two important objectives in organometallic chemistry are to understand C-H bond activation reactions mediated by transition metal compounds and then to develop efficient ways of functionalizing the resulting products. A particularly ambitious goal is the generation of metal carbenes from simple organic molecules; the synthetic chemist can then take advantage of the almost unlimited reactivity of this metal-organic functionality. This goal remains very difficult indeed with saturated hydrocarbons, but it is considerably more facile for molecules that possess a heteroatom (such as ethers), because coordination of the heteroatom to the metal renders the ensuing C-H activation an intramolecular reaction. In this Account, we focus on the activation reaction of different types of unstrained ethers, both aliphatic and hemiaromatic, by (mostly) iridium compounds. We emphasize our recent results with the Tp Me2Ir(C6H5)2(N2) (1A-N2) complex (where TpMe2 denotes hydrotris(3,5- dimethylpyrazolyl)borate). Most of the reactivity observed with this system, and with related electronically unsaturated iridium species, starts with a C-H activation reaction, which is then followed by reversible ∝-hydrogen elimination. An ∝-C-H bond is, in every instance, broken first; when there is a choice, cleavage of the stronger terminal Csp3-H bonds is always preferred over the weaker internal Csp 3-H (methylene) bonds of the ether. Nevertheless, competitive reactions of the unsaturated [TpMe2Ir(C6H5)2] iridium intermediate with ethers that contain Csp3-H and Csp2-H bonds are also discussed. We present theoretical evidence for a σ-complex-assisted metathesis mechanism (σ-CAM), although for other systems oxidative addition and reductive elimination events can be effective reaction pathways. We also show that additional unusual chemical transformations may occur, depending on the nature of the ether, and can result in C-O and C-C bond-breaking and bond-forming reactions, leading to the formation of more elaborate molecules. Although the possibility of extending these results to saturated hydrocarbons appears to be limited for this iridium system, the findings described in this Account are of fundamental importance for various facets of C-H bond activation chemistry, and with suitable modifications of the ancillary ligands, they could be even broader in scope. We further discuss experimental and theoretical studies on unusual alkene-to-alkylidene equilibria for some of the products obtained in the reactions of iridium complex 1N 2 with alkyl aryl ethers. The rearrangement involves reversible ∝- and β-hydrogen eliminations, with a rate-determining metal inversion step (supported by theoretical calculations); the alkylidene is always favored thermodynamically over the alkene. This startling result contrasts with the energetically unfavorable isomerization of free ethene to ethylidene (by about 80 kcal mol-1), showing that the tautomerism equilibrium can be directed toward one product or the other by a judicious choice of the transition metal complex. © 2010 American Chemical Society.

Campos J.,University of Seville | Esqueda A.C.,University of Seville | Carmona E.,University of Seville
Chemistry - A European Journal | Year: 2010

Cyclometallation of the bis(xylyl)phosphine PMe(Xyl)2 by [{(n5-C5Me5)IrCl2}2] and subsequent functionalization of the resulting compound was reported. The reaction was performed in the presence of the weakly coordinating base 2,2,6,6-tetramethylpiperidine (TTMP), giving the desired complex 1 in the form of two diastereomers. The Ir-CH 2 resonance appears at δ = 20.3 ppm and exhibits negligible coupling to phosphorus, whereas the two methyl groups of the nonmetallated xylyl show three-bond couplings. Since heating a solution of 4 in C6D6 at 200°C for two days reveals no D incorporation into the metallated ligand, intramolecular C-H activation of the nonmetallated Ir1 intermediate [(n5-C 5Me5)Ir(PMeXyl2)] proceeds much faster than intermolecular benzene activation.

James G.,French National Center for Scientific Research | Kevrekidis P.G.,University of Massachusetts Amherst | Cuevas J.,University of Seville
Physica D: Nonlinear Phenomena | Year: 2013

We prove nonexistence of breathers (spatially localized and time-periodic oscillations) for a class of Fermi-Pasta-Ulam lattices representing an uncompressed chain of beads interacting via Hertz's contact forces. We then consider the setting in which an additional on-site potential is present, motivated by the Newton's cradle under the effect of gravity. We show the existence of breathers in such systems, using both direct numerical computations and a simplified asymptotic model of the oscillator chain, the so-called discrete p-Schrödinger (DpS) equation. From a spectral analysis, we determine breather stability and explain their translational motion under very weak perturbations. Numerical simulations demonstrate the excitation of traveling breathers from simple initial conditions corresponding to small perturbations at the first site of the chain. This regime is well described by the DpS equation, and is found to occur for physical parameter values in granular chains with stiff local oscillators. In addition, traveling breather propagation can be hindered or even suppressed in other parameter regimes. For soft on-site potentials, a part of the energy remains trapped near the boundary and forms a surface mode. For hard on-site potentials and large to moderate initial excitations, one observes a "boomeron", i.e. a traveling breather displaying spontaneous direction-reversing motion. In addition, dispersion is significantly enhanced when a precompression is applied to the chain. Depending on parameters, this results either in the absence of traveling breather excitation on long time scales, or in the formation of a "nanopteron" characterized by a sizable wave train lying at both sides of the localized excitation. © 2013 Elsevier B.V. All rights reserved.

Hamedi J.,University of Tehran | Mohammadipanah F.,University of Tehran | Ventosa A.,University of Seville
Extremophiles | Year: 2013

More than 70 species of halotolerant and halophilic actinomycetes belonging to at least 24 genera have been validly described. Halophilic actinomycetes are a less explored source of actinomycetes for discovery of novel bioactive secondary metabolites. Degradation of aliphatic and aromatic organic compounds, detoxification of pollutants, production of new enzymes and other metabolites such as antibiotics, compatible solutes and polymers are other potential industrial applications of halophilic and halotolerant actinomycetes. Especially new bioactive secondary metabolites that are derived from only a small fraction of the investigated halophilic actinomycetes, mainly from marine habitats, have revealed the huge capacity of this physiological group in production of new bioactive chemical entities. Combined high metabolic capacities of actinomycetes and unique features related to extremophilic nature of the halophilic actinomycetes have conferred on them an influential role for future biotechnological applications. © 2012 Springer Japan.

Valverde J.M.,University of Seville
Research in Astronomy and Astrophysics | Year: 2016

A vast number of physical processes involving oscillations of a bounded viscous fluid are relevantly influenced by acoustic streaming. When this happens a steady circulation of fluid develops in a thin boundary adjacent to the interface. Some examples are refracted sound waves, a fluid inside a spherical cavity undergoing torsional oscillations or a pulsating liquid droplet. Steady streaming around circular interfaces consists of a hemispherically symmetric recirculation of fluid from the equatorial plane to the polar axes closely resembling the meridional circulation pattern observed in the Sun's convection zone that determines the solar cycle. In this paper, it is argued that the acoustic pulsations exhibited by the Sun would lead to acoustic streaming in the boundary of the convection zone. A simple estimation using a typical dominant frequency of 3 mHz and the observed surface oscillation amplitude yields a steady streaming velocity us ∼ 10 m s-1, which is on the order of the meridional circulation velocity observed in the Sun's convection zone. © 2016 National Astronomical Observatories, Chinese Academy of Sciences and IOP Publishing Ltd.

Olmedo E.,University of Seville
Journal of Forecasting | Year: 2016

In this paper we confirm the existence of nonlinear dynamics in a time series of airport arrivals. We subsequently propose alternative non-parametric forecasting techniques to be used in a travel forecasting problem, emphasizing the difference between the reconstruction and learning approach. We compare the results achieved in point prediction versus sign prediction. The reconstruction approach offers better results in sign prediction and the learning approach in point prediction. Copyright © 2015 John Wiley & Sons, Ltd.

Hernandez I.,University of Seville
AI Communications | Year: 2016

Integrating a web application into an automated business process requires to design wrappers that get user queries as input and map them onto the search forms that the application provides. Such wrappers build on automatic navigators which are responsible for navigating to the pages that provide the information required to answer the original user queries. A navigator relies on a web page classifier that discerns which pages provide the information and which do not. In the literature, there are many proposals to classify web pages, but none of them fulfills the requirements for a web page classifier in a navigator context. We address the problem of designing an unsupervised web page classifier that builds solely on the information provided by the URLs and does not require extensive crawling of the site being analysed. Our contribution is CALA, a new automated proposal to generate URL-based web page classifiers. Its salient features are that it does not need to previously crawl the complete web site, it is unsupervised, it does not require to download a page before classifying it, and it is computationally tractable. It has been validated by a number of experiments using real-world, top-visited web sites. © 2016 - IOS Press and the authors. All rights reserved.

Galera S.,University of Seville | Gutierrez Ortiz F.J.,University of Seville
Energy Conversion and Management | Year: 2015

Abstract The environmental performance of hydrogen and electricity production by supercritical water reforming (SCWR) of glycerol was evaluated following a Life Cycle Assessment (LCA) approach. The heat-integrated process was designed to be energy self-sufficient. Mass and energy balances needed for the study were performed using Aspen Plus 8.4, and the environmental assessment was carried out through SimaPro 8.0. CML 2000 was selected as the life cycle impact assessment method, considering as impact categories the global warming, ozone layer depletion, abiotic depletion, photochemical oxidant formation, eutrophication, acidification, and cumulative energy demand. A distinction between biogenic and fossil CO2 emissions was done to quantify a more realistic GHG inventory of 3.77 kg CO2-eq per kg H2 produced. Additionally, the environmental profile of SCWR process was compared to other H2 production technologies such as steam methane reforming, carbon gasification, water electrolysis and dark fermentation among others. This way, it is shown that SCWR of glycerol allows reducing greenhouse gas emissions and obtaining a favorable positive life cycle energy balance, achieving a good environmental performance of H2 and power production by SCWR of glycerol. © 2015 Elsevier Ltd. All rights reserved.

Valverde J.M.,University of Seville | Sanchez-Jimenez P.E.,University of Seville | Perez-Maqueda L.A.,University of Seville
Applied Energy | Year: 2015

The low cost and wide availability of natural limestone (CaCO3) is at the basis of the industrial competitiveness of the Ca-looping (CaL) technology for postcombustion CO2 capture as already demonstrated by ~1Mwt scale pilot projects. A major focus of studies oriented towards further improving the efficiency of the CaL technology is how to prevent the gradual loss of capture capacity of limestone derived CaO as the number of carbonation/calcination cycles is increased. Natural dolomite (MgCa(CO3)2) has been proposed as an alternative sorbent precursor to limestone. Yet, carbonation of MgO is not thermodynamically favorable at CaL conditions, which may hinder the capture performance of dolomite. In the work described in this paper we carried out a thermogravimetric analysis on the multicyclic capture performance of natural dolomite under realistic regeneration conditions necessarily implying high calcination temperature, high CO2 concentration and fast transitions between the carbonation and calcination stages. Our study demonstrates that the sorbent derived from dolomite has a greater capture capacity as compared to limestone. SEM analysis shows that MgO grains in the decomposed dolomite are resistant to sintering under severe calcination conditions and segregate from CaO acting as a thermally stable support which mitigates the multicyclic loss of CaO conversion. Moreover, full decomposition of dolomite is achieved at significantly lower calcination temperatures as compared to limestone, which would help improving further the industrial competitiveness of the technology. © 2014 Elsevier Ltd.

Sanchez-De-Armas R.,University of Seville | San Miguel M.A.,University of Seville | Oviedo J.,University of Seville | Sanz J.F.,University of Seville
Physical Chemistry Chemical Physics | Year: 2012

Time dependent density functional theory (TD-DFT) calculations have been carried out to study the electronic structure and the optical properties of five coumarin based dyes: C343, NKX-2311, NKX-2586, NKX-2753 and NKX-2593. We have found out that the position and width of the first band in the electronic absorption spectra, the absorption threshold and the LUMO energy with respect to the conduction band edge are key parameters in order to establish some criteria that allow evaluating the efficiency of coumarin derivatives as sensitizers in Dye Sensitized Solar Cells (DSSC). Those criteria predict the efficiency ordering for the coumarin series in good agreement with the experimental evidence. Presumably, they might be used in the design of new efficient organic based DSSC.

Abstract Nowadays, solar thermophotovoltaic systems constitute a platform in which sophisticated optical material designs are put into practice with the aim of achieving the long sought after dream of developing an efficient energy conversion device based on this concept. Recent advances demonstrate that higher efficiencies are at reach using photonic nanostructures amenable to mass production and scale-up. Thermal cylinders eat light: Efficient utilization of sunlight can be regarded as the solution to future energy crises. In particular, solar thermophotovoltaics has long borne the promise to convert solar light into electricity in the most efficient way. However, they have not fulfilled their potential up to now, mainly due to the lack of large-scale materials that can absorb and emit light at high temperatures. Herein, a new approach to improving light harvesting of such devices is highlighted. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Delgado V.,University of Seville | Marques R.,University of Seville
Optics Express | Year: 2011

Extraordinary Optical Transmission of TM waves impinging at oblique incidence on metallic or high permittivity dielectric screens with a periodic distribution of 1D slits or any other kind of 1D defects is analyzed. Generalized waveguide theory altogether with the surface impedance concept are used for modeling such phenomena. A numerical analysis based on the mode matching technique proves to be an efficient tool for the characterization of these structures for any angle of incidence and slit or defect apertures. © 2011 Optical Society of America.

Guzman H.,University of Malaga | Barrero F.,University of Seville | Duran M.J.,University of Malaga
IEEE Transactions on Industrial Electronics | Year: 2015

Multiphase machine drives are gaining importance in high-reliability applications due to their fault-tolerance capability and their ability to cope with the postfault operation without any extra electronic components. Predictive current controllers have been recently proposed for managing postfault operation of these drives when an open-phase fault is considered. However, the faulty situation assumes zero stator current while freewheeling diodes can continue conducting in a noncontrolled mode. This work analyzes the postfault operation of the five-phase drive when the freewheeling diodes of the faulty phase are still conducting. Experimental results are provided using a conventional insulated-gate bipolar transistor (IGBT)-based multiphase power converter to quantify the effect of the freewheeling diodes, when an IGBT-gating fault occurs, on the model-based predictive current-controlled drive. © 1982-2012 IEEE.

McConnell M.J.,University of Seville | Rumbo C.,Complexo Hospitalario Universitario runa | Bou G.,Complexo Hospitalario Universitario runa | Pachon J.,University of Seville
Vaccine | Year: 2011

Acinetobacter baumannii produces different types of infections including pneumonia, meningitis, and bloodstream infections. The optimal treatment of these infections has been complicated by the global emergence of multidrug resistant strains, requiring the development of novel approaches for treatment and prevention. Outer membrane vesicles are outpouchings of the bacterial outer membrane that are secreted from numerous pathogenic Gram-negative bacteria. In the present study, we describe the isolation of outer membrane vesicles from A. baumannii and their use as a vaccine in a mouse model of disseminated sepsis. Immunization produced a robust antibody response against multiple bacterial antigens which consisted of antigen-specific IgG and IgM. In addition, both IgG1 and IgG2c subtypes were produced by immunization. Immunized mice had lower tissue bacterial loads and lower serum levels of the pro-inflammatory cytokines IL-6 and IL-1β post-infection compared to control mice. Importantly, vaccination protected mice from challenge with the ATCC 19606 strain and provided protection against two clinical isolates, including a pan-resistant strain. These results indicate that vaccination with outer membrane vesicles may be a viable strategy for preventing A. baumannii infection. © 2011 Elsevier Ltd.

Ferris C.,University of Seville | De Paz M.V.,University of Seville | Galbis J.A.,University of Seville
Journal of Polymer Science, Part A: Polymer Chemistry | Year: 2011

Three new polymerizable diols, based on mono-, di-, and tri-O-allyl-L-arabinitol derivatives, were prepared from L-arabinitol as versatile materials for the preparation of tailor-made polyurethanes with varied degrees of functionalization. Their allyl functional groups can take part in thiol-ene reactions, to obtain greatly diverse materials. This "click" reaction with 2-mercaptoethanol was firstly studied on the highly hindered sugar precursor 2,3,4-tri-O-allyl-1,5-di-O-trityl-L-arabinitol, to apply it later to macromolecules. A polyurethane with multiple pendant allyl groups was synthesized by polyaddition reaction of 2,3,4-tri-O-allyl-L-arabinitol with 1,6-hexamethylene diisocyanate, and then functionalized by thiol-ene reaction. The coupling reaction took place in every allyl group, as confirmed by standard techniques. The thermal stability of the novel polyurethanes was investigated by thermogravimetric analysis and differential scanning calorimetry (DSC). This strategy provides a simple and versatile platform for the design of new materials whose functionality can be easily modified. © 2010 Wiley Periodicals, Inc.

Baison-Olmo F.,University of Seville | Cardenal-Munoz E.,University of Seville | Ramos-Morales F.,University of Seville
Biochemical and Biophysical Research Communications | Year: 2012

Salmonella harbors two type III secretion systems, T3SS1 and T3SS2, encoded on the pathogenicity islands SPI1 and SPI2, respectively. Several effector proteins are secreted through these systems into the eukaryotic host cells. PipB2 is a T3SS2 effector that contributes to the modulation of kinesin-1 motor complex activity. Here, we show that PipB2 is also a substrate of T3SS1. This result was obtained infecting human epithelial HeLa cells for 2. h and was confirmed in murine RAW264.7 macrophages, and rat NRK fibroblasts. Analysis at different time points after infection revealed that translocation of PipB2 is T3SS1-dependent in epithelial cells throughout the infection. In contrast, translocation into macrophages is T3SS1-dependent during invasion but T3SS2-dependent at later time points. The N-terminal 10 amino acid residues contain the signal necessary for translocation through both systems. These results confirm the functional overlap between these virulence-related secretion systems and suggest a new role for the effector PipB2. © 2012 Elsevier Inc.

Rodriguez-Berral R.,University of Seville | Mesa F.,University of Seville | Medina F.,University of Seville
Applied Physics Letters | Year: 2010

This paper proposes an equivalent circuit model that uses lumped elements and transmission lines to explain the transmission of electromagnetic waves through a conducting screen periodically perforated with slits and sandwiched between two different dielectric slabs. The present model relies on the impedance-matching point of view, previously introduced by some of the authors, rather than on the surface plasmon polariton concept. Thus, the model constitutes a simple and insightful framework that easily leads to accurate qualitative and quantitative predictions about the nature of the transmission spectrum of such structures. © 2010 American Institute of Physics.

Lozano S.,University of Seville
Expert Systems with Applications | Year: 2015

Abstract Many real-world production processes generate pollution as an undesirable but inevitable by-product. Identifying, measuring and removing existing inefficiencies can simultaneously increase productivity and benefit the environment. Recently, a pollution generating production technology has been proposed with two distinct processes: a production process and a pollution generation process. This paper uses the novel concept of joint inputs to formulate a parallel-processes Network DEA approach that uses a non-oriented, Network Slacks-Based Measure of efficiency (NSBM) model to assess the efficiency of the overall system and of the individual processes. No previous Network DEA approach had considered joint inputs. In addition, the proposed Network DEA approach improves over existing methods since, among other interesting features, it uses Linear Programming and it identifies all input and output inefficiencies. The proposed approach is rather general and can thus be applied to all production processes involving pollution generation. Numerical results for two datasets, one involving 92 coal-fired power plants and the other 23 EU and OECD countries, are presented. © 2015 Elsevier Ltd.

Garcia-Torres F.,Simulation and Control Unit | Bordons C.,University of Seville
IEEE Transactions on Industrial Electronics | Year: 2015

The electricity market rules determine the energy prices in the day-ahead market, matching offers from generators to bids from consumers. The unpredictability of renewable energy combined with the penalty deviations used in the regulation market makes it difficult for clean energy to play an important role in the electricity market. The high density of hydrogen as an energy storage system (ESS) appears to be one solution to the problems outlined. There is still not a perfect ESS, everyone has different limitations from the point of view of time autonomy, time response, degradation issues, or acquisition cost. The design of a hybrid energy storage management system emerges as a technological solution to the problems commented. The development of an optimal control for renewable energy microgrids with hybrid ESS is carried out using model predictive control (MPC). The MPC techniques allow maximizing the economical benefit of the microgrid, minimizing the degradation causes of each storage system, and fulfilling the different system constraints. In order to capture both continuous/discrete dynamics and switching between different operating conditions, the plant is modeled with the framework of mixed logic dynamic. The MPC problem is solved within mixed-integer quadratic programming. © 2015 IEEE.

Cruces S.,University of Seville
IEEE Transactions on Signal Processing | Year: 2015

Our paper addresses the problem of the bounded component analysis of the observations in noisy mixtures. We present an original set of assumptions that guarantee the identifiability of the mixture in underdetermined mixtures and the separability of the sources in overdetermined mixtures. These assumptions are especially well suited for the blind identification of communication channels. Our proof of the identifiability of the mixing system is non-constructive. Thus, we develop a novel blind identification criterion for underdetermined and overdetermined mixtures, which is based on the least square fit of the perimeter of a set of projections of the observations. For the optimization of this criterion we propose the BCA-PM algorithm, which implements the natural gradient descent, along with an acceleration of the convergence designed for the neighbourhood of the solution. In situations of isotropic Gaussian noise and for reasonable signal to noise ratio, BCA-PM compares favorably with respect to other state-of-the-art methods, such as the ICA simultaneous diagonalization algorithms for underdetermined and overdetermined mixtures. The simulations also corroborate the advantages of using bounded component analysis for the blind identification of the channel with small datasets or when the transmitters cannot be regarded as statistically independent. © 2015 IEEE.

Sharaf M.A.,Suez Canal University | Nafey A.S.,Suez Canal University | Garcia-Rodriguez L.,University of Seville
Energy | Year: 2011

Solar power assisted different techniques of MED-VC (multi effect distillation-vapor compression) processes is thermo-economically analyzed and evaluated. In this work, two techniques of solar power cycles are considered to power on MED-PF-TVC, MVC (multi effect distillation thermal and mechanical vapor compressions). In the first technique, the developed solar thermal power is directly transmitted from the solar collector field via boiler heat exchanger unit toward the steam ejector of the MED-PF-TVC process. In the second technique, the electrical power generated from the SORC (Solar Organic Rankine Cycle) is used to power on the vapor compressor of the MED-PF-MVC process. The comparison is implemented according to the operation of PTC (parabolic trough collector) with Toluene organic oil and Water working fluids (2nd technique). Therminol-VP1 HTO (Heat Transfer Oil) is considered across the solar field and water is considered for boiler heat exchanger (1st technique). A case study is performed according to 4545 m3/day of distillate product. As a result, reducing the value of compression ratio with increasing the evaporator's numbers would reduce the specific power consumption, solar field area, and thermo-economic costs. Also it is clear that the operation of steam ejector would increase the gain ratio instead of increasing the evaporator's numbers. © 2011 Elsevier Ltd.

Gomez-Quiles C.,University of Seville | De La Villa Jaen A.,University of Seville | Gomez-Exposito A.,University of Seville
IEEE Transactions on Power Systems | Year: 2011

This paper presents a factorized state estimation methodology based on the solution of two successive WLS problems. In the proposed scheme, a minimal set of intermediate variables is first introduced so that the resulting measurement model is linear. Estimates of those variables are then used as pseudo-measurements of a subsequent nonlinear estimator, along with the associated covariance matrix. The aim of the preliminary step is to reduce the size of the raw measurement vector to the maximum extent, without losing any relevant statistical information. Simulation results show that the proposed approach converges faster, is computationally more efficient, and provides accurate estimates after the first linear stage. © 2011 IEEE.

Marquez A.M.,University of Seville | Plata J.J.,University of Seville | Ortega Y.,University of Seville | Fdez. Sanz J.,University of Seville
Journal of Physical Chemistry C | Year: 2011

In this Article, the structural and electronic properties of the W-doped anatase (101) surface are investigated by first-principles density functional theory calculations. Several surface and subsurface substitutional positions are examined as well as the interaction of the W-dopant atoms with structural defects: cation vacant sites and additional oxygen atoms that are required to compensate the extra charge of the W6+ cations. It is found that the preferred configurations are those on which one W6+ cation and one Ti vacant site are first cationic neighbors with simultaneous formation of a wolframyl entity. The main mechanism of system stabilization is found to be based on the formation of wolframyl species that result from the close proximity, as first cationic neighbors of the W-dopant atom and the Ti vacant site. A second factor for system stabilization seems to be the separation of W6+ cations to reduce the energetic cost of the structural distortions introduced by the doping process. Results from molecular dynamics calculations indicate that W6+ cations have a 5 + 1 coordination with two W-O distances at 1.8 to 2.0 and 2.5 to 2.6 Å. All of these structural results are used to understand the experimental information available for W-Ti nanostructured oxides. The modifications introduced in the electronic structure of the anatase (101) surface by the doping process are discussed and rationalized. A comparative analysis of the density of states of doped and undoped slab models of this surface and a Bader charge analysis will be used to understand the electronic redistribution that takes place around the impurity atoms. © 2011 American Chemical Society.

Gonzalez J.S.,University of Seville | Rodriguez T.G.,University of Jaén | Burgos Payan M.,University of Seville | Santos J.R.,University of Seville
Renewable Energy | Year: 2011

An Evolutive Algorithm (EA) for wind farm optimal overall design is presented. The algorithm objective is to optimize the profits given an investment on a wind farm. Net Present Value (NPV) will be used as a figure of the revenue in the proposed method. To estimate the NPV is necessary to calculate the initial capital investment and net cash flow throughout the wind farm life cycle. The maximization of the NPV means the minimization of the investment and the maximization of the net cash flows (to maximise the generation of energy and minimise the power losses). Both terms depend mainly on the number and type of wind turbines, the tower height and geographical position, electrical layout, among others. Besides, other auxiliary costs must be to keep in mind to calculate the initial investment such as the cost of auxiliary roads or tower foundations. The difficulty of the problem is mainly due to the fact that there is neither analytic function to model the wind farm costs nor analytic function to model net generation. The complexity of this problem arises not only from a technical point of view, due to strong links between its variables, but also from a purely mathematical point of view. The problem consists of both discrete and continuous variables, being therefore an integer-mixed type problem. The problem exhibits manifold optimal solutions (convexity), some variables have a range of non allowed values (solutions space not simply connected) and others are integers. This fact makes the problem non-derivable, preventing the use of classical analytical optimization techniques. © 2010 Elsevier Ltd.

Gomez-Quiles C.,University of Seville | Gil H.A.,University of Seville
IEEE Transactions on Power Systems | Year: 2011

The revenue that wind farms produce is subject to the inherent uncertainty of the wind resource in the short-run and the long-term. This revenue is subject to an additional price-related uncertainty in jurisdictions where the output of the wind farms is paid at the prices cleared at the local electricity market. An econometric model is developed to estimate the risks of using limited information in the estimation of the annual revenue of a wind farm. Sensitivities that measure the influence of each uncertainty factor in the overall risks are also developed. An application example is shown by which investors or policy-makers may determine how typical wind farm capital costs may influence financial project feasibility under a predetermined risk. © 2006 IEEE.

Sanchez-Romero M.A.,University of Seville | Cota I.,University of Seville | Casadesus J.,University of Seville
Current Opinion in Microbiology | Year: 2015

Formation of C5-methyl-cytosine, N4-methyl-cytosine, and N6-methyl-adenine in bacterial genomes is postreplicative, and occurs at specific targets. Base methylation can modulate the interaction of DNA-binding proteins with their cognate sites, and controls chromosome replication, correction of DNA mismatches, cell cycle-coupled transcription, and formation of epigenetic lineages by phase variation. During four decades, the roles of DNA methylation in bacterial physiology have been investigated by analyzing the contribution of individual methyl groups or small methyl group clusters to the control of DNA-protein interactions. Nowadays, single-molecule real-time sequencing can analyze the DNA methylation of the entire genome (the 'methylome'). Bacterial methylomes provide a wealth of information on the methylation marks present in bacterial genomes, and may open a new era in bacterial epigenomics. © 2015 Elsevier Ltd.

Gonzalez-Garcia L.,University of Seville | Gonzalez-Valls I.,Catalan Institute of Nanoscience and Nanotechnology | Lira-Cantu M.,Catalan Institute of Nanoscience and Nanotechnology | Barranco A.,University of Seville | Gonzalez-Elipe A.R.,University of Seville
Energy and Environmental Science | Year: 2011

Transparent thin film electrodes made of vertically aligned nanocolumns of TiO 2 with well-controlled oblique angles were grown by physical vapor deposition at glancing incidence (PVD-GLAD). For an electrode thickness of 500 nm, we report a 40% variation on solar cell efficiency (from 0.6% to 1.04%) when the deposition angle was modified between 60° and 85°. Transparent thicker films with higher surface area deposited at the optimal angle of 70° were grown with a zigzag morphology which confers high mechanical strength to the thin films. Using this topology, the application of an electrode thickness of 3 m in a DSC resulted in a power conversion efficiency of 2.78% maintaining electrode transparency. © 2011 The Royal Society of Chemistry.

Del Pino Lopez J.C.,University of Seville | Romero P.C.,University of Seville
IEEE Transactions on Power Delivery | Year: 2011

This paper analyzes the thermal effects derived from the use of different screen shapes when shielding the magnetic field generated by underground power cables. A parametric analysis is developed to show the influence of the geometrical and the electrical parameters of the shield on the maximum temperature achieved by the power cables in order to analyze the impact of this technique on the ampacity of the line. A 2-D finite element approach is employed in this study to verify the performance of different types of screens (horizontal plate, reverse-U, and H-layout) in terms of shielding efficiency, overheating of the power cables, and operational costs. © 2011 IEEE.

Neves D.,University of Aveiro | Neves D.,Chalmers University of Technology | Thunman H.,Chalmers University of Technology | Matos A.,University of Aveiro | And 2 more authors.
Progress in Energy and Combustion Science | Year: 2011

In this study some literature data on the pyrolysis characteristics of biomass under inert atmosphere were structured and analyzed, constituting a guide to the conversion behavior of a fuel particle within the temperature range of 200-1000 °C. Data is presented for both pyrolytic product distribution (yields of char, total liquids, water, total gas and individual gas species) and properties (elemental composition and heating value) showing clear dependencies on peak temperature. Empirical relationships are derived from the collected data, over a wide range of pyrolysis conditions and considering a variety of fuels, including relations between the yields of gas-phase volatiles and thermochemical properties of char, tar and gas. An empirical model for the stoichiometry of biomass pyrolysis is presented, where empirical parameters are introduced to close the conservation equations describing the process. The composition of pyrolytic volatiles is described by means of a relevant number of species: H2O, tar, CO2, CO, H2, CH4 and other light hydrocarbons. The model is here primarily used as a tool in the analysis of the general trends of biomass pyrolysis, enabling also to verify the consistency of the collected data. Comparison of model results with the literature data shows that the information on product properties is well correlated with the one on product distribution. The prediction capability of the model is briefly addressed, with the results showing that the yields of volatiles released from a specific biomass are predicted with a reasonable accuracy. Particle models of the type presented in this study can be useful as a submodel in comprehensive reactor models simulating pyrolysis, gasification or combustion processes. © 2010 Elsevier Ltd. All rights reserved.

Santolina impressa (2n = 2x = 18) is an endemic species of Portugal, with restricted geographical distribution. The present study aimed to explore its chromosomal variation in respect to chromosome morphology, meiotic behaviour, and effects on pollen stainability and fecundity. Its karyotype formula was found to be either 12m + 2msat + 2smsat + 2st (75% of the individuals) or 12m + 2msat + 3sm + 1smsat (25% of the individuals). Univalents were observed in 29.21% of the meiocytes. Chromosome fragments due to breakage in the chromosome arm were observed in 10 meiocytes only (11.23% of the meiocytes). Chains and rings of trivalents were observed in 14.60% of the meiocytes (one trivalent per meiocyte was observed). Chains and rings of quadrivalents were observed in 21.34% and 11.23% of the meiocytes, respectively, with a range of 0-1 per cell. Nine plants (40.90% of the total) with 2n = 2x = 18 + 2B showed a quadrivalent configuration in diakinesis. Twenty abnormal anaphases with delayed disjunction of the four non-homologous and the two homologous chromosomes were observed. Simple chromosome bridges without fragments and interchromosomal adhesions were observed in 35.95% of the anaphases analyzed. B chromosomes showed bivalent association in diakinesis and their segregation at anaphase I was normal. Pollen was found to be fertile (mean ± s.d. = 89.57 ± 47.14%); the effect of univalent frequency and frequency of abnormal anaphase I on pollen stainability was strong and statistically significant. © Institute of Botany, Academy of Sciences of the Czech Republic 2009.

Penate B.,Canary Islands Institute of Technology ITC | Garcia-Rodriguez Lourdes L.,University of Seville
Energy | Year: 2011

Reduction of SEC (specific energy consumption) is the field with the most specific technical research focus and effort in SWRO (seawater reverse osmosis) plants. For existing installations with energy recovery systems consisting in Pelton turbines, the most significant challenge is how to reduce energy costs. The highest efficient isobaric ERD (energy recovery devices) are used in order to produce major savings in energy consumption in the desalination process and/or to increase the freshwater capacity of the installations, by taking full advantage of the plant equipment. This paper gives a brief overview of the technology used to recover the energy from brine stream in large desalination plants, with a description of the modifications required if the recovery system with Pelton turbines is to be replaced by systems based on isobaric-chamber devices. All possibilities analysed are deeply justified technically and thermoeconomically within an exhaustive assessment. © 2010 Elsevier Ltd.

Garnacho-Montero J.,University of Seville | Amaya-Villar R.,University of Seville
Current Opinion in Infectious Diseases | Year: 2010

Purpose of review: We present recent data about epidemiology of Acinetobacter baumannii in the hospital setting, major resistance mechanisms, and therapeutic options for infections caused by multidrug-resistant strains. Recent findings: A. baumannii has emerged as a major cause of healthcare-associated infections. It commonly presents resistance to multiple antimicrobial agents, including carbapenems. These strains are now ussually resistant to the rest of antipseudomonal β-lactams and sulbactam, a β-lactamase inhibitor with bactericide activity against A. baumannii. Rifampicin has demonstrated its effectiveness in animal models but can never be used in monotherapy because of the rapid development of resistance. Colistin, an old antibiotic, has re-emerged as a valid alternative given its excellent in-vitro activity. Numerous studies have confirmed its efficacy in serious infections, including ventilator-associated pneumonia and nosocomial meningitis, with an acceptable safety profile. Tigecycline appears as a promising therapeutic option for multidrug resistant A. baumannii, althogh more clinical data about its efficacy especially in pulmonary infections are required. The role of combination therapy or the use or colistin in alternative routes (nebulized or intrathecally) has not been established. Summary: The optimal treatment for multidrug-resistant A. baumannii nosocomial infections has not been established. Carbapenems are the mainstay of treatment in susceptible isolates. Colistin and tigecycline retain good in-vitro activity and in many cases represent the only therapeutic options. © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Lopez-Campos J.L.,University of Seville | Lopez-Campos J.L.,CIBER ISCIII | Ruiz-Ramos M.,Consejeria de Salud y Bienestar Social de Andalucia. Seville | Soriano J.B.,Fundacion Caubet Cimera
The Lancet Respiratory Medicine | Year: 2014

Background: Findings from studies done over the past 20 years suggest that mortality from chronic obstructive pulmonary disease (COPD) is decreasing worldwide, but little information is available for trends in Europe. We aimed to describe COPD mortality trends by sex and calendar year for the period of 1994 to 2010. Methods: We extracted data for COPD deaths between 1994 and 2010 in the 27 countries in the European Union (EU) from the statistical office of the EU (Eurostat), using the International Classification of Diseases 10 (ICD-10) codes J40-J44 and J47. We estimated age-standardised mortality rates (ASR), and analysed data using joinpoint regression, for women and men in the EU overall and by individual country for each year. We used the standard European population as the reference and present our findings as deaths per 100000 person-years. We compared findings for each country with the EU average by calculating standardised rate ratios (SRR) and 95% CIs. Findings: Between 1994 and 2010, there were 2348184 recorded COPD deaths in the EU. COPD mortality was higher in men than in women throughout the study period in all EU countries. In the EU overall, deaths per 100000 population decreased in men almost linearly from 90·07 in 1994 to 61·33 in 2010, and in women from 26·99 in 1994 to 25·15 in 2010, representing a narrowing in gender gap over the study period. Several countries had a higher SRR mortality than the EU average-eg, Ireland, Hungary, and Belgium for men and Denmark, the UK, and the Netherlands for women. Our joinpoint regression analysis identified no statistically significant changes in the trend for the whole EU, but several countries had changing trends over the study period. In men, we recorded a 2·56% constant and statistically significant decrease in ASRs in the EU. Five countries had an increase in ASR. Overall, in women, we recorded a 0·76% statistically significant decrease in ASRs. 14 countries had an increase in ASR. Interpretation: Our findings indicate a downward trend in COPD mortality in Europe between 1994 and 2010. The data also suggest a narrowing of the gap between COPD mortality in men and in women. The wide heterogeneity in mortality rates within European countries could serve as a reference to allow informed policy making. Funding: None. © 2014 Elsevier Ltd.

Garcia-Martinez J.,University of Seville | Adam A.L.,Szent Istvan University | Avalos J.,University of Seville
PLoS ONE | Year: 2012

The ascomycete fungus Fusarium fujikuroi (Gibberella fujikuroi MP-C) produces secondary metabolites of biotechnological interest, such as gibberellins, bikaverin, and carotenoids. Production of these metabolites is regulated by nitrogen availability and, in a specific manner, by other environmental signals, such as light in the case of the carotenoid pathway. A complex regulatory network controlling these processes is recently emerging from the alterations of metabolite production found through the mutation of different regulatory genes. Here we show the effect of the targeted mutation of the acyA gene of F. fujikuroi, coding for adenylyl cyclase. Mutants lacking the catalytic domain of the AcyA protein showed different phenotypic alterations, including reduced growth, enhanced production of unidentified red pigments, reduced production of gibberellins and partially derepressed carotenoid biosynthesis in the dark. The phenotype differs in some aspects from that of similar mutants of the close relatives F. proliferatum and F. verticillioides: contrary to what was observed in these species, ΔacyA mutants of F. fujikuroi showed enhanced sensitivity to oxidative stress (H 2O 2), but no change in heavy metal resistance or in the ability to colonize tomato tissue, indicating a high versatility in the regulatory roles played by cAMP in this fungal group. © 2012 García-Martínez et al.

Garnacho-Montero J.,Hospital Universitario Virgen del Rocio | Garnacho-Montero J.,University of Seville | Ferrandiz-Millon C.,Hospital Universitario Virgen del Rocio
Critical Care | Year: 2014

Few antimicrobials are currently active to treat infections caused by extremely resistant Gram-negative bacilli (ERGNB), which represent a serious global public health concern. Tigecycline, which covers the majority of these ERGNB (with the exception of Pseudomonas aeruginosa), is not currently approved for hospital-acquired pneumonia, and several meta-analyses have suggested an increased risk of death in patients receiving this antibiotic. Other studies suggest that the use of high-dose tigecycline may represent an alternative in daily practice. De Pascale and colleagues report that the clinical cure rate in patients with ventilator-associated pneumonia is significantly higher with a high dose of tigecycline than with the conventional dose, although mortality was unaffected. This high dose is safe; no patients required discontinuation or dose reduction. © 2014 Garnacho-Montero and Ferrándiz-Millón; licensee BioMed Central Ltd.

Romero-Gomez M.,University of Seville | Montagnese S.,University of Padua | Jalan R.,University College London
Journal of Hepatology | Year: 2015

Hepatic encephalopathy in a hospitalized cirrhotic patient is associated with a high mortality rate and its presence adds further to the mortality of patients with acute-on-chronic liver failure (ACLF). The exact pathophysiological mechanisms of HE in this group of patients are unclear but hyperammonemia, systemic inflammation (including sepsis, bacterial translocation, and insulin resistance) and oxidative stress, modulated by glutaminase gene alteration, remain as key factors. Moreover, alcohol misuse, hyponatremia, renal insufficiency, and microbiota are actively explored. HE diagnosis requires exclusion of other causes of neurological, metabolic and psychiatric dysfunction. Hospitalization in the ICU should be considered in every patient with overt HE, but particularly if this is associated with ACLF. Precipitating factors should be identified and treated as required. Evidence-based specific management options are limited to bowel cleansing and non-absorbable antibiotics. Ammonia lowering drugs, such as glycerol phenylbutyrate and ornithine phenylacetate show promise but are still in clinical trials. Albumin dialysis may be useful in refractory cases. Antibiotics, prebiotics, and treatment of diabetes reduce systemic inflammation. Where possible and not contraindicated, large portalsystemic shunts may be embolized but liver transplantation is the most definitive step in the management of HE in this setting. HE in patients with ACLF appears to be clinically and pathophysiologically distinct from that of acute decompensation and requires further studies and characterization. © 2014 European Association for the Study of the Liver.

Lozano S.,University of Seville
Computers and Industrial Engineering | Year: 2015

Abstract In this paper a slacks-based measure (SBM) model for general networks of processes is presented. The proposed model differs from existing SBM Network Data Envelopment Analysis (DEA) approaches in that it considers the exogenous inputs and outputs at the system level instead of at the process level. It also relaxes the constraints for both the fixed-link and the free-link cases, thus enhancing the discriminating power of the model. To assess the performance of the individual processes an external efficiency model is presented. The proposed approach projects the system operation point onto the efficient frontier so that the target operation points of the different processes are externally efficient. The approach is illustrated with a problem from the literature. © 2015 Elsevier Ltd.

Borras A.,University of Seville | Gonzalez-Elipe A.R.,University of Seville
Langmuir | Year: 2010

This work presents a thorough study on the wettability of polycrystalline anatase TiO2 thin films prepared at 250 °C in a microwave plasma enhanced chemical vapor deposition (MW-PECVD) reactor with Ar/O2 plasmas. Anatase polycrystalline thin films with different microstructures, textures, and surface roughness were obtained as a function of their thickness. The water contact angle of the samples was analyzed within the assumptions of the Wenzel, Cassie, and Miwa models to ascertain the effect of roughness and other surface heterogeneities on their characteristic parameters. The roughness factors defined in the different models were calculated from the atomic force microscopy (AFM) images of the films for two different observation scales within the premises of the dynamic scaling theories. The obtained results indicate that the wetting angle of an equivalent flat anatase surface with a value of 82° can only be properly estimated for observation scales of 5 × 5 μm2 and using the Miwa model. The analysis of the UV induced hydrophilization of the surface state of the anatase films and the posterior recovery of the partially hydrophobic character of these surfaces in the absence of UV photons suggest a clear dependence of the light induced wettability on their texture and size of crystalline domains. © 2010 American Chemical Society.

Ortiz A.L.,University of Extremadura | Sanchez-Bajo F.,University of Extremadura | Cumbrera F.L.,University of Seville | Guiberteau F.,University of Extremadura
Journal of Applied Crystallography | Year: 2013

A worked example of polytypism is presented, aimed at assisting undergraduates in the learning and instructors in the teaching of this topic. In particular, this crystallography concept, not necessarily obvious for beginners, is illustrated pedagogically using to that end the model case of the prolific polytypism of silicon carbide (SiC). On the basis of concepts that are easily assimilated by students (i.e. simple topological constraints) this article first presents a unified description of the polytypism phenomenon in SiC that allows one to understand without difficulty the existence of its numerous polytypic variants and how they develop. Then the various notations used to designate these different polytypes are described, and finally the crystal structures of the most common are discussed. This worked example is thus expected to contribute to motivating undergraduates in the study of a crystallography topic that often is not treated in sufficient depth in class. © 2013 International Union of Crystallography.

Antinolo G.,University of Seville
BMC pregnancy and childbirth | Year: 2014

BACKGROUND: Indications for the ex utero intrapartum therapy (EXIT) procedure have evolved and nowadays in addition to secure the airway, obtain vascular access, administer surfactant and other resuscitation medications, EXIT is used to resect cervical or thoracic masses, for extracorporeal membrane circulation (ECMO) cannulation, as well as to rescue maximum intra-thoracic space for ventilation of the remaining functional lung tissue or in cases in which resuscitation of the neonate may be compromised. EXIT procedure in twin pregnancy has been rarely reported and some doubts have been raised about its strategy and safety in such cases.METHODS: We reviewed the medical records of 3 twin pregnancy cases where the EXIT procedure have been performed in our center.RESULTS: The mean gestational age at EXIT procedure was 34 + 4 weeks. In two out the three EXIT procedures, the affected twin was delivered first. The average time on placental bypass was 9 minutes. There were no fetal or maternal complications related to the EXIT procedure. All newborns are currently doing well.CONCLUSION: In twin pregnancies, prenatal diagnosis combined with the EXIT procedure permits the formulation of a controlled delivery strategy to secure both newborns outcome. In those pregnancies, if intervention can be accomplished without compromise of the normal twin, EXIT can be considered. Our results support that EXIT procedure, if properly planned, safely provides a good outcome for both the fetuses as well as the mother.

Torres-Lagares D.,University of Seville
Journal (Canadian Dental Association) | Year: 2011

A large maxillary cyst was treated for 3 months with marsupialization and decompression, followed by surgical endodontic therapy of the affected teeth and cystectomy. Although small cystic lesions will typically heal with nonsurgical endodontic therapy, larger lesions may need additional treatment. Surgical enucleation of a large cystic lesion may lead to damage of other teeth or anatomic structures. Therefore, treatment should begin with the more conservative approach of decompression, to reduce the size of the lesion, followed by apicoectomy and cystectomy.

Galan-Marin C.,University of Seville | Rivera-Gomez C.,University of Seville | Petric J.,University of Strathclyde
Construction and Building Materials | Year: 2010

The research objective is the stabilization of soils with natural polymers and fibres to produce a composite, sustainable, non-toxic and locally sourced building material. Mechanical tests have been conducted with a clay soil supplied by a Scottish brick manufacture. Alginate (a natural polymer from the cell walls of brown algae) has been used as bonding in the composite. Sheep's wool was used as reinforcement. Tests done showed that the addition of alginate separately increases compression strength from 2.23 to 3.77 MPa and the addition of wool fibre increases compression strength a 37%. The potential benefit of stabilization was found to depend on the combinations of both stabilizer and wool fibre. Adding alginate and reinforcing with wool fibre doubles the soil compression resistance. Better results were obtained with a lower quantity of wool. © 2010 Elsevier Ltd.

Vergara-Lopez S.,Hospital La Merced | Dominguez M.C.,Hospital La Merced | Conejo M.C.,University of Seville | Pascual A.,University of Seville | Rodriguez-Bano J.,University of Seville
Clinical Microbiology and Infection | Year: 2013

We describe the epidemiology of a protracted nosocomial clonal outbreak due to multidrug-resistant IMP-8 producing Klebsiella oxytoca (MDRKO) that was finally eradicated by removing an environmental reservoir. The outbreak occurred in the ICU of a Spanish hospital from March 2009 to November 2011 and evolved over four waves. Forty-two patients were affected. First basic (active surveillance, contact precautions and reinforcement of surface cleaning) and later additional control measures (nurse cohorting and establishment of a minimum patient/nurse ratio) were implemented. Screening of ICU staff was repeatedly negative. Initial environmental cultures, including dry surfaces, were also negative. The above measures temporarily controlled cross-transmission but failed to eradicate the epidemic MDRKO strain that reappeared two weeks after the last colonized patients in waves 2 and 3 had been discharged. Therefore, an occult environmental reservoir was suspected. Samples from the drainpipes and traps of a sink were positive; removal of the sink reduced the rate number but did not stop new cases that clustered in a cubicle whose horizontal drainage system was connected with the eliminated sink. The elimination of the horizontal drainage system finally eradicated the outbreak. In conclusion, damp environmental reservoirs (mainly sink drains, traps and the horizontal drainage system) could explain why standard cross-transmission control measures failed to control the outbreak; such reservoirs should be considered even when environmental cultures of surfaces are negative. ©2013 European Society of Clinical Microbiology and Infectious Diseases.

Gekle S.,University of Twente | Peters I.R.,University of Twente | Gordillo J.M.,University of Seville | Van Der Meer D.,University of Twente | Lohse D.,University of Twente
Physical Review Letters | Year: 2010

A solid object impacting on liquid creates a liquid jet due to the collapse of the impact cavity. Using visualization experiments with smoke particles and multiscale simulations, we show that in addition, a high-speed air jet is pushed out of the cavity. Despite an impact velocity of only 1m/s, this air jet attains supersonic speeds already when the cavity is slightly larger than 1 mm in diameter. The structure of the air flow closely resembles that of compressible flow through a nozzle-with the key difference that here the "nozzle" is a liquid cavity shrinking rapidly in time. © 2010 The American Physical Society.

Plastria F.,Vrije Universiteit Brussel | Carrizosa E.,University of Seville
4OR | Year: 2014

One recently proposed criterion to separate two data sets in Classification is to use a hyperplane that minimizes the sum of distances to it from all the misclassified data points, where misclassification means lying on the wrong side of the hyperplane, or rather in the wrong halfspace. In this paper we study an extension of this problem: we seek the hyperplane minimizing the sum of concave nondecreasing functions of the distances of misclassified points to it. It is shown that an optimal hyperplane exists containing at least d affinely independent points. This extends the result known for the minimization of the sum of distances, and enables to use combinatorial local-search heuristics for this problem. As a corollary, the same result is obtained for the approximation problem in which a hyperplane minimizing the sum of concave nondecreasing functions of the distances from a set of data points is sought. © 2013 Springer-Verlag Berlin Heidelberg.

Lozano S.,University of Seville
Fuzzy Sets and Systems | Year: 2014

In this paper, a new approach to compute estimations of the process efficiencies in two-stage systems with fuzzy data is presented. The first step is to compute the upper and lower limits of the α-cuts of the system efficiency using the corresponding models in Kao and Liu (2011) [14]. The second step consists in computing the upper and lower limits of the α-cuts of the efficiency of each of the processes. The upper limit of the α-cuts of the efficiency of each process is computed subject to the upper limit of the system efficiency while the lower limit of the process efficiency is computed subject to the lower limit of the system efficiency. The proposed approach takes into account the inherent uncertainty regarding the process efficiencies even in the crisp data case. The approach is illustrated with a dataset from the literature. © 2013 Elsevier B.V.

Duran A.J.,University of Seville
Journal of Combinatorial Theory. Series A | Year: 2014

Let (pn)n be a sequence of orthogonal polynomials with respect to the measure μ. Let T be a linear operator acting in the linear space of polynomials P and satisfying deg(T(p)) = deg(p) - 1, for all polynomial p. We then construct a sequence of polynomials (sn)n, depending on T but not on μ, such that the Wronskian type n × n determinant det(Ti-1(pm+j-1(x)))i,j=1n is equal to the m × m determinant det(qn+i-1j-1(x))i,j=1m, up to multiplicative constants, where the polynomials qni, n, i ≥ 0, are defined by qni(x)=∑j=0nμjisn-j(x), and μji are certain generalized moments of the measure μ. For T = d/. d x we recover a theorem by Leclerc which extends the well-known Karlin and Szego identities for Hankel determinants whose entries are ultraspherical, Laguerre and Hermite polynomials. For T = δ, the first order difference operator, we get some very elegant symmetries for Casorati determinants of classical discrete orthogonal polynomials. We also show that for certain operators T, the second determinant above can be rewritten in terms of Selberg type integrals, and that for certain operators T and certain families of orthogonal polynomials (pn)n, one (or both) of these determinants can also be rewritten as the constant term of certain multivariate Laurent expansions. © 2014 Elsevier Inc.

Fernandez-Viagas V.,University of Seville | Framinan J.M.,University of Seville
Computers and Operations Research | Year: 2014

The most efficient approximate procedures so far for the flowshop scheduling problem with makespan objective - i.e. the NEH heuristic and the iterated greedy algorithm - are based on constructing a sequence by iteratively inserting, one by one, the non-scheduled jobs into all positions of an existing subsequence, and then, among the so obtained subsequences, selecting the one yielding the lowest (partial) makespan. This procedure usually causes a high number of ties (different subsequences with the same best partial makespan) that must be broken via a tie-breaking mechanism. The particular tie-breaking mechanism employed is known to have a great influence in the performance of the NEH, therefore different procedures have been proposed in the literature. However, to the best of our knowledge, no tie-breaking mechanism has been proposed for the iterated greedy. In our paper, we present a new tie-breaking mechanism based on an estimation of the idle times of the different subsequences in order to pick the one with the lowest value of the estimation. The computational experiments carried out show that this mechanism outperforms the existing ones both for the NEH and the iterated greedy for different CPU times. Furthermore, embedding the proposed tie-breaking mechanism into the iterated greedy provides the most efficient heuristic for the problem so far. © 2013 Elsevier Ltd.

Martinez-Roman J.A.,University of Seville | Gamero J.,University of Seville | Tamayo J.A.,University of Seville
Technovation | Year: 2011

This article analyzes organizational characteristics associated with innovative outcomes of SMEs in local economies with a low level of technological and R&D activities, where the indicators generally used to gauge technological innovation do not offer sufficient data. For the study of innovation in such economies, we propose a conceptual model based on innovative capability which also includes explanatory variables of environment and other contextual factors of the firms. Through a process of filtering spurious variables and incorporating quadratic components, we have varied the original linear structure to form a quadratic model with greater explanatory capacity and better results. The resulting quadratic model has undergone various contrasts of hypotheses, thus demonstrating the effectiveness of the model as a whole and of its basic components, as well as the importance of the main explanatory variables. Finally, the model has also proven to be valid in all sectors. © 2011 Elsevier Ltd.

Bernard M.,TU Berlin | Kondak K.,German Aerospace Center | Maza I.,University of Seville | Ollero A.,University of Seville
Journal of Field Robotics | Year: 2011

It is generally accepted that systems composed of multiple aerial robots with autonomous cooperation capabilities can assist responders in many search and rescue (SAR) scenarios. In most of the previous research work, the aerial robots are mainly considered as platforms for environmental sensing and have not been used to assist victims. In this paper, outdoor field experiments of transportation and accurate deployment of loads with single/multiple autonomous aerial vehicles are presented. This is a novel feature that opens the possibility to use aerial robots to assist victims during rescue phase operations. Accuracy in the deployment location is a critical issue in SAR scenarios in which injured people may have very limited mobility. The presented system is composed of up to three small-size helicopters and features cooperative sensing, using several different sensor types. The system supports several forms of cooperative actuation as well, ranging from the cooperative deployment of small sensors/objects to the coupled transportation of slung loads. The complete system is described, outlining the hardware and software framework used, as well as the approaches for modeling and control used. Additionally, the results of several flight field experiments are presented, including a description of the worldwide first successful autonomous load transportation experiment, using three coupled small-size helicopters (conducted in December 2007). During these experiments strong, steady winds and wind gusts were present. Various solutions and lessons learned from the design and operation of the system are also provided. Copyright © 2011 Wiley Periodicals, Inc.

Lozano S.,University of Seville | Gutierrez E.,University of Seville
Computers and Industrial Engineering | Year: 2011

In this paper, a multiobjective DEA approach to airlines target setting has been proposed allowing for more control and flexibility in the determination of the trade-offs among environmental impact, fleet cost and operating cost. These variables are considered as inputs. Revenue Tonne-Kilometres (RTK) is the single output considered. For each airline, the proposed multiobjective Linear Programming model is solved using ADBASE, which finds all extreme efficient points in the Pareto Frontier. The representation of the Pareto Frontier as a function of RTK gives cues about the growth of the inputs and about their trade-offs with increasing output. Also, the technical efficiency of each airline has been assessed using a Slacks-Based Measure (SBM) of efficiency. The results show that about half of the airlines are technically inefficient and that most of the airlines operate below their Most Productive Scale Size which suggests that more industry consolidation is foreseeable in the future. Overall, although operating costs seem to be under control, there is an 8% overcapacity in terms of assets and a 7.2% excess carbon emissions. There is also room for an additional 4.4% overall traffic increase. © 2011 Elsevier Ltd. All rights reserved.

Gomez-Exposito A.,University of Seville | Abur A.,Northeastern University | De La Villa Jaen A.,University of Seville | Gomez-Quiles C.,University of Seville
Proceedings of the IEEE | Year: 2011

The main objective of this paper is to describe a multilevel framework that facilitates seamless integration of existing state estimators (SEs) that are designed to function at different levels of modeling hierarchy in order to accomplish very large-scale monitoring of interconnected power systems. This has been a major challenge for decades as power systems grew pretty much independently in different areas, which had to operate in an interconnected and synchronized fashion. The paper initially provides a brief historical perspective which also explains the existing state estimation paradigm. This is followed by a review of the recent technological and regulatory drivers that are responsible for the new developments in the energy management functions. The paper then shows that a common theoretical framework can be used to implement a hierarchical scheme by which even very large-scale power systems can be efficiently and accurately monitored. This is illustrated for substation level, transmission system level as well as for a level between different transmission system operators in a given power system. Finally, the paper describes the use and benefits of phasor measurements when incorporated at these different levels of the proposed infrastructure. Numerical examples are included to illustrate performance of the proposed multilevel schemes. © 2011 IEEE.

Sanchez-Lopez C.,University of Seville | Fernandez F.V.,University of Seville | Tlelo-Cuautle E.,National Institute of Astrophysics, Optics and Electronics | Tan S.X.-D.,University of California at Riverside
IEEE Transactions on Circuits and Systems I: Regular Papers | Year: 2011

This paper proposes new pathological element-based active device models which can be used in analysis tasks of linear(ized) analog circuits. Nullators and norators along with the voltage mirror-current mirror (VM-CM) pair (collectively known as pathological elements) are used to model the behavior of active devices in voltage-, current-, and mixed-mode, also considering parasitic elements. Since analog circuits are transformed to nullor-based equivalent circuits or VM-CM pairs or as a combination of both, standard nodal analysis can be used to formulate the admittance matrix. We present a formulation method in order to build the nodal admittance (NA) matrix of nullor-equivalent circuits, where the order of the matrix is given by the number of nodes minus the number of nullors. Since pathological elements are used to model the behavior of active devices, we introduce a more efficient formulation method in order to compute small-signal characteristics of pathological element-based equivalent circuits, where the order of the NA matrix is given by the number of nodes minus the number of pathological elements. Examples are discussed in order to illustrate the potential of the proposed pathological element-based active device models and the new formulation method in performing symbolic analysis of analog circuits. The improved formulation method is compared with traditional formulation methods, showing that the NA matrix is more compact and the generation of nonzero coefficients is reduced. As a consequence, the proposed formulation method is the most efficient one reported so far, since the CPU time and memory consumption is reduced when recursive determinant-expansion techniques are used to solve the NA matrix. © 2006 IEEE.

Perez-Gonzalez P.,University of Seville | Framinan J.M.,University of Seville
Computers and Operations Research | Year: 2010

In this paper we study a due date setting problem in a flowshop layout. The problem consists of scheduling a set of jobs arriving to the system together with jobs already present (denoted as old jobs), in order to set a common due date for the new jobs. Since the old jobs have a common due date that must not be violated, our problem is a rescheduling problem with the objective of minimising the makespan of the new jobs (thus obtaining the tightest possible due date for the new jobs) and a constraint since the maximum tardiness of the old jobs must be equal to zero. This approach leads to an interesting scheduling problem in which two different objectives are considered, each one for a subset of the jobs that must be scheduled. To the best of our knowledge, this type of problems have been scarcely considered in the literature, and only for very specific purposes. Since our problem is clearly NP-hard, a new heuristic based on variable neighbourhood search (VNS) has been designed. The computational results show that our proposed heuristic outperforms two existing heuristic methods for similar problems in the literature. © 2010 Elsevier Ltd. All rights reserved.

Armario J.A.,University of Seville
Cryptography and Communications | Year: 2010

Given two Hadamard matrices of the same order, it can be quite difficult to decide whether or not they are equivalent. There are some criteria to determine Hadamard inequivalence. Among them, one of the most commonly used is the 4-profile criterion. In this paper, a reformulation of this criterion in the cocyclic framework is given. The improvements obtained in the computation of the 4-profile of a cocyclic Hadamard matrix are indicated. © 2010 Springer Science + Business Media, LLC.

Paun G.,Romanian Academy of Sciences | Paun G.,University of Seville
Journal of Logic and Algebraic Programming | Year: 2010

Membrane computing is a branch of natural computing inspired from the architecture and the functioning of biological cells. The obtained computing models are distributed parallel devices, called P systems, processing multisets of objects in the compartments defined by hierarchical or more general arrangements of membranes. Many classes of P systems were investigated - mainly from the point of view of computing power and computing efficiency; also, a series of applications (especially in modeling biological processes) were reported. This note is a short and informal introduction to this research area, introducing a few basic notions, research topics, types of results, and pointing out to some relevant references. © 2010 Elsevier Inc. All rights reserved.

Tallon-Ballesteros A.J.,University of Seville | Hervas-Martinez C.,University of Cordoba, Spain
Expert Systems with Applications | Year: 2011

This paper presents a procedure to add broader diversity at the beginning of the evolutionary process. It consists of creating two initial populations with different parameter settings, evolving them for a small number of generations, selecting the best individuals from each population in the same proportion and combining them to constitute a new initial population. At this point the main loop of an evolutionary algorithm is applied to the new population. The results show that our proposal considerably improves both the efficiency of previous methodologies and also, significantly, their efficacy in most of the data sets. We have carried out our experimentation on twelve data sets from the UCI repository and two complex real-world problems which differ in their number of instances, features and classes. © 2010 Elsevier Ltd. All rights reserved.

Fernandez-Berni J.,University of Seville | Carmona-Galan R.,University of Seville | Carranza-Gonzalez L.,University of Seville
IEEE Journal of Solid-State Circuits | Year: 2011

This paper reports a 176× 144-pixel smart image sensor designed and fabricated in a 0.35μm CMOS-OPTO process. The chip implements a massively parallel focal-plane processing array which can output different simplified representations of the scene at very low power. The array is composed of pixel-level processing elements which carry out analog image processing concurrently with photosensing. These processing elements can be grouped into fully-programmable rectangular-shape areas by loading the appropriate interconnection patterns into the registers at the edge of the array. The targeted processing can be thus performed block-wise. Readout is done pixel-by-pixel in a random access fashion. On-chip 8b ADC is provided. The image processing primitives implemented by the chip, experimentally tested and fully functional, are scale space and Gaussian pyramid generation, fully-programmable multiresolution scene epresentationincluding foveationand block-wise energy-based scene representation. The power consumption associated to the capture, processing and A/D conversion of an image flow at 30 fps, with full-frame processing but reduced frame size output, ranges from 2.7 mW to 5.6 mW, depending on the operation to be performed. © 2011 IEEE.

Chalco-Cano Y.,University of Tarapacá | Roman-Flores H.,University of Tarapacá | Jimenez-Gamero M.D.,University of Seville
Information Sciences | Year: 2011

In this paper we study the generalized derivative and the π-derivative for interval-valued functions. We show the connections between these derivatives. Some illustrative examples and applications to interval differential equations and fuzzy functions are presented. © 2011 Elsevier Inc. All rights reserved.

Maestre J.M.,University of Seville | Munoz De La Pena D.,University of Seville | Camacho E.F.,University of Seville | Alamo T.,University of Seville
Journal of Process Control | Year: 2011

In this paper we consider the control of several subsystems coupled through the inputs by a set of independent agents that are able to communicate. We assume that each agent has access only to the model and the state of one of the subsystems. This implies that in order to take a cooperative decision, the agents must negotiate. At each sampling time agents make proposals to improve an initial feasible solution on behalf of their local cost function, state and model. These proposals are accepted if the global cost improves the cost corresponding to the current solution. In addition, we provide conditions that guarantee that the closed-loop system is asymptotically stable along with an optimization based design procedure that is based on the full model of the system. Finally, the proposed scheme is put to test through simulation. © 2010 Elsevier Ltd.

Lozano S.,University of Seville
Expert Systems with Applications | Year: 2011

In this paper a simple way of computing technical, scale, cost and allocative efficiency scores for homogeneous networks of processes is presented. The system Production Possibility Set (PPS) is formed through the composition of the PPS of the individual processes, which, in turn, are modelled in the conventional, axiomatic way using observed data. Firstly, the overall system scale and technical efficiency are computed using the relational network DEA approach. Local Returns To Scale (RTS) can also be estimated with these models. Secondly, assuming the prices of exogenous inputs are known, a minimum cost network DEA model is solved, from which cost and allocative efficiencies are derived. The proposed approach is illustrated with a two-stage problem from the literature, showing the usefulness of a more detailed problem assessment both in terms of technical and scale efficiency and RTS and in terms of cost and allocative efficiency. © 2010 Elsevier Ltd. All rights reserved.

Duran M.J.,University of Malaga | Prieto J.,University of Seville | Barrero F.,University of Seville | Toral S.,University of Seville
IEEE Transactions on Industrial Electronics | Year: 2011

Predictive control techniques have recently been applied with success to conventional and multiphase electrical drives. The additional degrees of freedom in multiphase drives make the real-time implementation of optimal solutions difficult due to the increased number of iterations. This paper proposes a predictive control technique that reduces the available voltage source inverter switching states according to predefined constraints. The introduced method, called as restrained search predictive control, favors on-line implementation and improves the current tracking performance. Simulation and experimental results are provided to test the viability of the presented technique. © 2009 IEEE.

Lozano S.,University of Seville | Villa G.,University of Seville | Canca D.,University of Seville
Computers and Industrial Engineering | Year: 2011

In this paper, we propose a number of non-radial, output-oriented, centralised DEA models to determine individual and collective output target levels, input slacks and input reallocations as well as additional inputs acquisitions under a capital budget constraint. The application of the proposed approach to the Spanish Port Agency is presented. The overall amount of inefficiency currently found in the system allows for the determination of potential total output increases ranging from 24% to 114% without additional resources. Considering inputs reallocation would allow for an additional 20% output expansion. The acquisition of additional input resources would make feasible to expand outputs further, to levels whose exact values monotonously depend on the capital budget considered. © 2010 Elsevier Ltd. All rights reserved.

Puerto J.,University of Seville | Ramos A.B.,University of Seville | Rodriguez-Chia A.M.,University of Cádiz
Computers and Operations Research | Year: 2011

The discrete ordered median location model is a powerful tool in modeling classic and alternative location problems that have been applied with success to a large variety of discrete location problems. Nevertheless, although hub location models have been analyzed from the sum, maximum and coverage point of views, as far as we know, they have never been considered under an alternative unifying point of view. In this paper we consider new formulations, based on the ordered median objective function, for hub location problems with new distribution patterns induced by the different users' roles within the supply chain network. This approach introduces some penalty factors associated with the position of an allocation cost with respect to the sorted sequence of these costs. First we present basic formulations for this problem, and then develop stronger formulations by exploiting properties of the model. The performance of all these formulations is compared by means of a computational analysis. © 2010 Elsevier Ltd. All rights reserved.

Here is reported the draft genome sequence of Methanobacterium formicicum DSM 3637, which was isolated from the methaneproducing amoeba Pelomyxa palustris. This bacterium was determined to be an endosymbiont living in the cytoplasm of P. palustris and the source of methane; however, the global characteristics of its genome suggest a free-living lifestyle rather than an endosymbiotic one. © 2012, American Society for Microbiology.

Van Ditmarsch H.,University of Seville
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

We review several logics with propositional quantification. © 2012 Springer-Verlag.

Obregon S.,University of Seville | Obregon S.,Sun Moon University | Lee S.W.,Sun Moon University | Colon G.,University of Seville
Dalton Transactions | Year: 2014

Er-doped BiVO4 are synthesized by means of a surfactant free microwave assisted hydrothermal method having good photoactivities under sun-like excitation for the degradation of methylene blue. From the structural and morphological characterization, it has been stated that the presence of Er3+ induces a slight stabilization of the tetragonal phase, probably due to its incorporation in the BiVO4 lattice. The best photocatalytic performances were attained for the samples with Er3+ content higher than 3 at%. The occurrence of the Er3+ doped tetragonal BiVO4 clearly induces higher photocatalytic activities. The existence of a luminescence process has been related with the enhanced photoactivity observed. © 2014 The Royal Society of Chemistry.

Liu B.,Catholic University of Leuven | Fernandez F.V.,University of Seville | Gielen G.G.E.,Catholic University of Leuven
IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems | Year: 2011

In nanometer complementary metal-oxide-semiconductor technologies, worst-case design methods and response-surface-based yield optimization methods face challenges in accuracy. Monte-Carlo (MC) simulation is general and accurate for yield estimation, but its efficiency is not high enough to make MC-based analog yield optimization, which requires many yield estimations, practical. In this paper, techniques inspired by computational intelligence are used to speed up yield optimization without sacrificing accuracy. A new sampling-based yield optimization approach, which determines the device sizes to optimize yield, is presented, called the ordinal optimization (OO)-based random-scale differential evolution (ORDE) algorithm. By proposing a two-stage estimation flow and introducing the OO technique in the first stage, sufficient samples are allocated to promising solutions, and repeated MC simulations of non-critical solutions are avoided. By the proposed evolutionary algorithm that uses differential evolution for global search and a random-scale mutation operator for fine tunings, the convergence speed of the yield optimization can be enhanced significantly. With the same accuracy, the resulting ORDE algorithm can achieve approximately a tenfold improvement in computational effort compared to an improved MC-based yield optimization algorithm integrating the infeasible sampling and Latin-hypercube sampling techniques. Furthermore, ORDE is extended from plain yield optimization to process-variation-aware single-objective circuit sizing. © 2011 IEEE.

Molina-Venegas R.,University of Seville | Roquet C.,CNRS Alpine Ecology Laboratory
Ecography | Year: 2014

Recent years have seen an increasing effort to incorporate phylogenetic hypotheses to the study of community assembly processes. The incorporation of such evolutionary information has been eased by the emergence of specialized software for the automatic estimation of partially resolved supertrees based on published phylogenies. Despite this growing interest in the use of phylogenies in ecological research, very few studies have attempted to quantify the potential biases related to the use of partially resolved phylogenies and to branch length accuracy, and no work has examined how tree shape may affect inference of community phylogenetic metrics. In this study, we tested the influence of phylogenetic resolution and branch length information on the quantification of phylogenetic structure, and also explored the impact of tree shape (stemminess) on the loss of accuracy in phylogenetic structure quantification due to phylogenetic resolution. For this purpose, we used 9 sets of phylogenetic hypotheses of varying resolution and branch lengths to calculate three indices of phylogenetic structure: the mean phylogenetic distance (NRI), the mean nearest taxon distance (NTI) and phylogenetic diversity (stdPD) metrics. The NRI metric was the less sensitive to phylogenetic resolution, stdPD showed an intermediate sensitivity, and NTI was the most sensitive one; NRI was also less sensitive to branch length accuracy than NTI and stdPD, the degree of sensitivity being strongly dependent on the dating method and the sample size. Directional biases were generally towards type II errors. Interestingly, we detected that tree shape influenced the accuracy loss derived from the lack of phylogenetic resolution, particularly for NRI and stdPD. We conclude that well-resolved molecular phylogenies with accurate branch length information are needed to identify the underlying phylogenetic structure of communities, and also that sensitivity of phylogenetic structure measures to low phylogenetic resolution can strongly vary depending on phylogenetic tree shape. © 2013 The Authors.

Mendez F.J.C.,University of Seville
Journal of Music, Technology and Education | Year: 2015

This study analyses the influence that new tools and resources in popular sequencing software have over the composition process. An analysis of the different resources of a software sequencer (Cubase 7) has been combined with a field study among 220 musicians from different countries that use this sequencer. A specially designed questionnaire has been used to collect information about the frequency use of different tools, the stage of use of them and the way the use of the sequencer influences their personal and professional development. The study has evidenced that certain tools have been fully incorporated into the composition process, while others are practically not used, or its use relies on different factors. The use of the sequencer has also clear positive effects on musicians and their creative process. Finally, the field research has helped to define and characterize different kinds of workflows in the composition process. © 2015 Intellect Ltd Article.

Troca-Marin J.A.,University of Seville | Alves-Sampaio A.,University of Seville | Montesinos M.L.,University of Seville
Journal of Neuroscience | Year: 2011

As in other diseases associated with mental retardation, dendrite morphology and synaptic plasticity are impaired in Down's syndrome (DS). Both these features of neurons are critically influenced by BDNF, which regulates local dendritic translation through phosphatidylinositol 3-kinase-Akt-mammalian target of rapamycin (mTOR) and Ras-ERK signaling cascades. Here we show that the levels of BDNF and phosphorylated Akt-mTOR (but not Ras-ERK) pathway proteins are augmented in hippocampal dendrites of Ts1Cje mice, a DS model. Consequently, the rate of local dendritic translation is abnormally high and the modulatory effect of exogenous BDNF is lost. Interestingly, rapamycin (a Food and Drug Administration-approved drug) restores normal levels of phosphorylated Akt-mTOR proteins and normal rates of local translation in Ts1Cje neurons, opening new therapeutic perspectives for DS. TheNMDARinhibitors APV, MK-801, and memantine also restore the normal levels of phospho-mTOR in dendrites of Ts1Cje hippocampal neurons. We propose a model to explain how BDNF-mediated regulation of local translation is lost in the Ts1Cje hippocampus through the establishment of a glutamatergic positive-feedback loop. Together, these findings help elucidate the mechanisms underlying altered synaptic plasticity in DS. © 2011 the authors.

Grueso E.,University of Seville | Cerrillos C.,University of Seville | Hidalgo J.,University of Seville | Lopez-Cornejo P.,University of Seville
Langmuir | Year: 2012

A multifaceted study on the interaction of the cationic surfactant CTAB with calf thymus DNA was carried out by using different techniques. The measurements were done at different molar ratios X = [CTAB]/[DNA]. Results show the conformational change that DNA suffers due to the interaction with surfactant molecules at low molar ratios: the condensation of the polynucleotide, from an extended coil state to a globular state. The effect observed at the higher molar ratios is worth noting: the decondensation of DNA, that is, the transition from a compact state to a more extended conformation. Experimental data obtained confirm that this latter state is not exactly the same as that found in the absence of the surfactant. Attractive interactions between different parts of the molecule by ion correlation effects are the driving force to produce both the compaction and decompaction events. Results also show the importance of choosing both a proper system for the study and the most seeming measuring technique to use. The study demonstrates that, in some cases, the use of several techniques is desirable in obtaining reliable and accurate results. © 2012 American Chemical Society.

Idnurm A.,University of Missouri - Kansas City | Verma S.,University of Missouri - Kansas City | Corrochano L.M.,University of Seville
Fungal Genetics and Biology | Year: 2010

Virtually all organisms exposed to light are capable of sensing this environmental signal. In recent years the photoreceptors that mediate the ability of fungi to " see" have been identified in diverse species, and increasingly characterized. The small sizes of fungal genomes and ease in genetic and molecular biology manipulations make this kingdom ideal amongst the eukaryotes for understanding photosensing. The most widespread and conserved photosensory protein in the fungi is White collar 1 (WC-1), a flavin-binding photoreceptor that functions with WC-2 as a transcription factor complex. Other photosensory proteins in fungi include opsins, phytochromes and cryptochromes whose roles in fungal photobiology are not fully resolved and their distribution in the fungi requires further taxon sampling. Additional unknown photoreceptors await discovery. This review discusses the effects of light on fungi and the evolutionary processes that may have shaped the ability of species to sense and respond to this signal. © 2010 Elsevier Inc.

Corrochano L.M.,University of Seville | Garre V.,University of Murcia
Fungal Genetics and Biology | Year: 2010

Light is an environmental signal that modulates many aspects of the biology of zygomycete fungi. Light regulation has been investigated in the zygomycetes Phycomyces blakesleeanus, Mucor circinelloides and Pilobolus crystallinus. Examples of light regulation include the phototropism of the fruiting bodies, the regulation of the development of reproductive structures, and the activation of the biosynthesis of β-carotene. In fungi blue light is perceived by proteins homologous to WC-1, a Neurospora crassa photoreceptor and Zn finger protein that interacts with WC-2 to form a photoresponsive transcription factor complex. Unlike ascomycete and basidiomycete fungi that usually have one wc-1 and one wc-2 gene, several studies have uncovered an unexpected multitude of genes similar to wc-1 and wc-2 in the genomes of several zygomycete fungi. Some of these genes are required for fungal photoresponses, but the function of many of them remains unknown. The presence of multiple wc-1 genes confirms previous suggestions of multiple blue-light photoreceptors in Phycomyces. © 2010 Elsevier Inc.

Avalos J.,University of Seville | Estrada A.F.,University of Basel
Fungal Genetics and Biology | Year: 2010

The genus Fusarium stands out as research model for pathogenesis and secondary metabolism. Light stimulates the production of some Fusarium metabolites, such as the carotenoids, and in many species it influences the production of asexual spores and sexual fruiting bodies. As found in other fungi with well-known photoresponses, the Fusarium genomes contain several genes for photoreceptors, among them a set of White Collar (WC) proteins, a cryptochrome, a photolyase, a phytochrome and two presumably photoactive opsins. The mutation of the opsin genes produced no apparent phenotypic alterations, but the loss of the only WC-1 orthologous protein eliminated the photoinduced expression of the photolyase and opsin genes. In contrast to other carotenogenic species, lack of the WC photoreceptor did not impede the light-induced accumulation of carotenoids, but produced alterations in conidiation, animal pathogenicity and nitrogen-regulated secondary metabolism. The regulation and functional role of other Fusarium photoreceptors is currently under investigation. © 2010 Elsevier Inc.

Lavado-Roldan A.,University of Seville | Fernandez-Chacon R.,University of Seville
PLoS Biology | Year: 2016

One of the most fascinating properties of the brain is the ability to function smoothly across decades of a lifespan. Neurons are nondividing mature cells specialized in fast electrical and chemical communication at synapses. Often, neurons and synapses operate at high levels of activity through sophisticated arborizations of long axons and dendrites that nevertheless stay healthy throughout years. On the other hand, aging and activity-dependent stress strike onto the protein machineries turning proteins unfolded and prone to form pathological aggregates associated with neurodegeneration. How do neurons protect from those insults and remain healthy for their whole life? Ali and colleagues now present a molecular mechanism by which the enzyme nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2) acts not only as a NAD synthase involved in axonal maintenance but as a molecular chaperone helping neurons to overcome protein unfolding and protein aggregation. © 2016 Lavado-Roldán, Fernández-Chacón.

This study presents a systematized method for predicting water content, fat content and free acidity in olive fruits by on-line NIR Spectroscopy combined with chemometric techniques (PCA, LDA and PLSR). Three cultivar varieties of Olea europaea - Hojiblanca cv., Picual cv. and Arbequina cv. - were monitored. Five olive cultivation areas of Southern Spain (Andalucia) and Southern Portugal (Alentejo) were studied in 2011 and 2012. 465 olive samples were collected during the ripening process (non-mature olives) and compared with other 203 samples of mature olives collected at the final ripening stage. NIR spectra were measured directly in the olive fruits in the wavelength region from 1000 to 2300 nm in reflectance mode. The reference analyses were performed on the olive paste by oven drying for the moisture, by mini-Soxhlet extraction for the fat content and by acid titration of the oil extracted from the olive paste. Calibrations and predictive models were developed by Partial Least Square Regression (PLSR) previous Principal Component and Linear Discriminant analyses (PCA and LDA) were employed as exploratory and clean-up tools of data sets. The final models obtained for the total samples showed acceptable statistics of prediction with R2=0.88, RMSEV%=4.88 and RMSEP%=4.98 for water content, R2=0.76, RMSECV%=19.5 and RMSEP%=20.0 for fat content and R2=0.83, RMSECV%=36.8 and RMSEP%=38.8 for free acidity. Regression coefficients were better for only one maturity state (ripe period) than for olive fruit with different composition (ripening period). All models obtained were applied to predict LQPs on a new set of samples with satisfactory results, a good prediction potential of the models. © 2015 Elsevier B.V. All rights reserved.

Rondon A.G.,University of Seville | Jimeno S.,University of Seville | Aguilera A.,University of Seville
Biochimica et Biophysica Acta - Gene Regulatory Mechanisms | Year: 2010

Eukaryotic gene expression is a multilayer process covering transcription to post-translational protein modifications. As the nascent pre-mRNA emerges from the RNA polymerase II (RNAPII), it is packed in a messenger ribonucleoparticle (mRNP) whose optimal configuration is critical for the normal pre-mRNA processing and mRNA export, mRNA integrity as well as for transcription elongation efficiency. The interplay between transcription and mRNP formation feeds forward and backward and involves a number of conserved factors, from THO to THSC/TREX-2, which in addition have a unique impact on transcription-dependent genome instability. Here we review our actual knowledge of the role that these factors play at the interface between transcription and mRNA export in the model organism Saccharomyces cerevisiae. © 2010 Elsevier B.V.

Moriel-Carretero M.,University of Seville | Aguilera A.,University of Seville
Cell Cycle | Year: 2010

Failures in Nucleotide Excision Repair (NER) are generally associated with extreme sun sensitivity, high cancer risks and neurodegeneration. This is explained by the inability to repair UV lesions and oxidative damage, and may be ascribed to a deficiency in the TFIIH complex, which has a dual role in NER and transcription initiation. We have recently uncovered the molecular basis for a specific TFIIH component deficiency, Rad3/XPD, whose consequences are drastically different from other NER failures. Yeast rad3-102 cells partially process NER damage beyond the incision step but do not refill the generated ssDNA gap, as a consequence leading to replication fork breakage. Double-strand breaks are therefore generated that need to be repaired by a Rad52 and MRX-dependent homologous recombination mechanism, which promotes replication re-start via two alternative pathways, one Rad51-dependent, the other Pol32-dependent. On the basis of this study we revisit and discuss our actual view of replication fork breakage and re-start and the molecular mechanisms that explain XPD-associated diseases. © 2010 Landes Bioscience.

Fernandez J.J.,University of Seville
Genetics and molecular research : GMR | Year: 2012

Modifications in the GABA pathway are considered to be responsible for motor alterations in animal models for fragile X-associated tremor ataxia syndrome. We analyzed the expression profile in the cerebellum in a transgenic mouse model that over expresses the human FMR1 gene with CGG repeats in the normal range. We used the "GeneChip Mouse Gene 1.0 ST Array" from Affymetrix analyzing 28,853 well-described and -characterized genes. Based on data from the comparative analysis of the expression profile, we detected a significant gradient with a P value <0.1 and changes in expression equal to or greater than 1.5 times compared to the control mouse genes. There were significant changes in the expression of 104 genes, among which 72% had decreased and 28% had increased expression. With the exception of GabarapL2, no changes in expression of genes from the GABA pathway were observed, which may explain the absence of an altered motor phenotype in these mice. These results further support the view that toxic effects in fragile X-associated tremor ataxia syndrome are due to expansion of CGG repeats rather than increased mRNA levels, since in the transgenic mice the FMR1 mRNA levels were increased 20-100 times compared with those of control littermates.

Vaquero-Sedas M.I.,University of Seville | Vega-Palas M.A.,University of Seville
Scientific Reports | Year: 2014

In humans, telomere length studies have acquired great relevance because the length of telomeres has been related to natural processes like disease, aging and cancer. However, very little is known about the influence of telomere length on the biology of wild type plants. The length of plant telomeres has been usually studied by Terminal Restriction Fragment (TRF) analyses. This technique requires high amounts of tissue, including multiple cell types, which might be the reason why very little is known about the influence of telomere length on plant natural processes. In contrast, many of the human telomere length studies have focused on homogenous cell populations. Most of these studies have been performed by PCR, using telomeric degenerated primers, which allow the determination of telomere length from small amounts of human cells. Here, we have adapted the human PCR procedure to analyze the length of Arabidopsis thaliana telomeres. This PCR approach will facilitate the analysis of telomere length from low amounts of tissue. We have used it to determine that CG and non CG DNA methylation positively regulates Arabidopsis telomere length.

Lapine M.,University of Sydney | Jelinek L.,Czech Technical University | Marques R.,University of Seville
Optics Express | Year: 2012

While the effective medium treatment of unbounded metamaterials appears to be well established and firmly proven, related phenomena in finite structures have not received sufficient attention. We report on mesoscopic effects associated with the boundaries of finite discrete metamaterial samples, which can invalidate an effective medium description. We show how to avoid such effects by proper choice of boundary configuration. As all metamaterial implementations are naturally finite, we are confident that our findings are crucial for future metamaterial research. © 2012 Optical Society of America.

Klippstein R.,University of Seville | Pozo D.,University of Seville
Nanomedicine: Nanotechnology, Biology, and Medicine | Year: 2010

Dendritic cells (DCs) are potent antigen-presenting cells capable of initiating a primary immune response and possess the ability to activate T cells and stimulate the growth and differentiation of B cells. DCs provide a direct connection between innate and adaptive immune response, and arise from bone marrow precursors that are present in immature forms in peripheral tissues, where they are prepared to capture antigens. DCs migrate from the peripheral tissues to the closest lymph nodes through afferent lymphatic vessels to present the foreign antigens, stimulating T-cell activation and initiating a cellular immune response. Moreover, it is known that DCs have an important role in various diseases and conditions involving the immune system, particularly in cancer and autoimmune disorders. For these reasons, targeting nanoparticles (NPs) to DCs provides a promising strategy for developing an efficient balanced and protective immune response. NPs can modulate the immune response and might be potentially useful as effective vaccine adjuvants for infectious disease and cancer therapy. The objective of this review is to present the latest advances in NP delivery methods targeting DCs, the mechanisms of action, potential effects, and therapeutic results of these systems and their future applications, such as improved vaccination strategies, cancer immunotherapy, and immunomodulatory treatments. From the Clinical Editor: Dendritic cells (DCs) are potent antigen-presenting cells capable of initiating a primary immune response and activating T and B cells. The role of DC-s can be considered as a bridge between innate and adaptive immunity. Targeting nanoparticles (NPs) to DCs can modulate the immune response and might be useful as vaccine adjuvants in infectious disease and cancer therapy. © 2010 Elsevier Inc.

Aolita L.,ICFO - Institute of Photonic Sciences | Gallego R.,ICFO - Institute of Photonic Sciences | Cabello A.,University of Seville | Cabello A.,University of Stockholm | And 2 more authors.
Physical Review Letters | Year: 2012

Local measurements on bipartite maximally entangled states can yield correlations that are maximally nonlocal, monogamous, and with fully random outcomes. This makes these states ideal for bipartite cryptographic tasks. Genuine-multipartite nonlocality constitutes a stronger notion of nonlocality in the multipartite case. Maximal genuine-multipartite nonlocality, monogamy, and random outcomes are thus highly desired properties for genuine-multipartite cryptographic scenarios. We prove that local measurements on any Greenberger-Horne-Zeilinger state can produce correlations that are fully genuine-multipartite nonlocal, monogamous, and with fully random outcomes. A key ingredient in our proof is a multipartite chained Bell inequality detecting genuine-multipartite nonlocality, which we introduce. Finally, we discuss applications to device-independent secret sharing. © 2012 American Physical Society.

Moro A.M.,University of Seville | Lay J.A.,University of Seville
Physical Review Letters | Year: 2012

The phenomenon of core excitation in the breakup of a two-body halo nucleus is investigated. We show that this effect plays a significant role in the reaction dynamics and, furthermore, its interference with the valence excitation mechanism has sizable and measurable effects on the breakup angular distributions. These effects have been studied in the resonant breakup of Be11 on a carbon target, populating the resonances at 1.78MeV (5/2+) and 3.41MeV (3/2+). The calculations have been performed using a recent extension of the distorted-wave Born approximation method, which takes into account the effect of core excitation in both the structure of the halo nucleus and in the reaction mechanism. The calculated angular distributions have been compared with the available data. Although each of these resonances is dominated by one of the two considered mechanisms, the angular patterns of these resonances depend in a very delicate way on the interference between them. This is the first clear evidence of this effect but the phenomenon is likely to occur in other similar reactions. © 2012 American Physical Society.

Law J.Y.,Nanyang Technological University | Franco V.,University of Seville | Ramanujan R.V.,Nanyang Technological University
Applied Physics Letters | Year: 2011

The magnetic entropy change (Δ SM), temperature of peak Δ SM (Tpk) and refrigerant capacity (RC) in Fe (RE)80 B12 Cr8 (RE=La, Ce, or Gd) alloys were studied. Increasing La, Ce, and Gd content led to relatively constant, decrease, and increase in Tpk, respectively. Both the phenomenologically constructed universal curve for Δ SM and field dependence power laws demonstrated that these alloys exhibited similar critical exponents at Curie temperature. With 5% Ce added to Fe80 B12 Cr 8, Tpk could be tuned near room temperature with relatively constant peak Δ SM. Fe79 B12 Cr8 La1 exhibited enhanced RC compared to Gd5 Si2 Ge1.9 Fe0.1. The tunable Tpk and enhanced RC are needed in active magnetic regenerators. © 2011 American Institute of Physics.

Morales-Conde S.,University of Seville
Hernia | Year: 2012

Introduction Laparoscopic techniques are being used increasingly in the repair of ventral hernias, but different incidences and complications have been described as potential risks of this approach. Seroma formation has been documented as one of the most common complication, although most of the time remains asymptomatic and it can be considered just an incident. The incidence of seroma after laparoscopic ventral hernia repair has not been properly documented and analyzed since the definitionused by different authors is not the same from one series to another. We present a new classification of clinical seroma in order to try to establish the real incidence of this potential complication. Clinical classification Clinical seromas could be detected during physical examination in many patients after LVHR, but in most of the cases they do not cause any problem or just a minimum discomfort that allows normal activity. Based on this fact and on the need of carrying out a medical or an invasive therapy to treat them, five groups can be established in order to classified this entity: Type 0, no clinical seroma (being 0a no seroma after clinical examination and radiological examinations and 0b those detected radiologically but not detected clinically); Type I, clinical seroma lasting less than 1 month; Type II (seroma with excessive duration), clinical seroma lasting more than 1 month (being IIa between 1 and 3 months and IIb between 3 and 6 months); Type III (symptomatic seromas that may need medical treatment), minor seromarelated complications (seroma lasting more than 6 month, esthetic complaints of the patient due to seroma, discomfort related to the seroma that does not allow normal activity to the patient, pain, superficial infection with cellulites); and Type IV (seroma that need to be treated), mayor seroma-related complications (need to puncture the seroma, seroma drained spontaneously, applicable to open approach, deep infection, recurrence and mesh rejection). It is important to differentiate between a complication and an incident, being considered seroma as an incident if it is classified as seroma Type I or II, and a complication if it is included in group III and IV. The highest classification is the one that should be used in order to describe the type of seroma. Conclusions Seroma is one of the most common complications after laparoscopic ventral hernia repair although its real clinical incidence is variable since it has been described in the literature following different parameters. It is observed in almost all cases by radiological examinations, but it is not determined if must be considered an incident or a complication. For these reasons, a new classification of seroma has been proposed in order to unify criteria among surgeons when describing their experience. This classification could be also used in the future to measure the effect of new methods proposed to reduce seroma formation to evaluate the incidence of seroma depending on the mesh used, and it could be also proposed to be used to describe the incidence of seroma after open ventral hernia repair. © Springer-Verlag 2012.

Guillen-gonzalez F.,University of Seville | Tierra G.,University of Seville
Journal of Computational Physics | Year: 2013

Numerical schemes to approximate the Cahn-Hilliard equation have been widely studied in recent times due to its connection with many physically motivated problems. In this work we propose two type of linear schemes based on different ways to approximate the double-well potential term. The first idea developed in the paper allows us to design a linear numerical scheme which is optimal from the numerical dissipation point of view meanwhile the second one allows us to design unconditionally energy-stable linear schemes (for a modified energy). We present first and second order in time linearschemes to approximate the CH problem, detailing their advantages over other linear schemes that have been previously introduced in the literature. Furthermore, we compare all the schemes through several computational experiments. © 2012 Elsevier Inc.

This thesis introduces three contributions to train feed-forward neural network models based on evolutionary computation for a classification task. The new methodologies have been evaluated in three-layered neural models, including one input, one hidden and one output layer. Particularly, two kind of neurons such as product and sigmoidal units have been considered in an independent fashion for the hidden layer. Experiments have been carried out in a good number of problems, including three complex real-world problems, and the overall assessment of the new algorithms is very outstanding. Statistical tests shed light on that significant improvements were achieved. The applicability of the proposals is wide in the sense that can be extended to any kind of hidden neuron, either to other kind of problems like regression or even optimization with special emphasis in the two first approaches. © 2016-IOS Press and the authors. All rights reserved.

Lai L.B.,Ohio State University | Vioque A.,University of Seville | Kirsebom L.A.,Uppsala University | Gopalan V.,Ohio State University
FEBS Letters | Year: 2010

For an enzyme functioning predominantly in a seemingly housekeeping role of 5′ tRNA maturation, RNase P displays a remarkable diversity in subunit make-up across the three domains of life. Despite the protein complexity of this ribonucleoprotein enzyme increasing dramatically from bacteria to eukarya, the catalytic function rests with the RNA subunit during evolution. However, the recent demonstration of a protein-only human mitochondrial RNase P has added further intrigue to the compositional variability of this enzyme. In this review, we discuss some possible reasons underlying the structural diversity of the active sites, and use them as thematic bases for elaborating new directions to understand how functional variations might have contributed to the complex evolution of RNase P. © 2009 Federation of European Biochemical Societies.

Nepomuceno-Chamorro I.A.,University of Seville
AI Communications | Year: 2016

We propose a novel methodology to infer gene association networks from gene expression profiles (microarray data) based on the application of model tree. We first build a regression tree for each gene and second, we build a graph from all the linear relationships among output and input genes taking into account whether the pair of genes is statistically significant. Then, we apply a statistical procedure to control the false discovery rate. Part of this methodology is a key component in a predictionbased method for a cardiovascular problem based on the discovery of clinically relevant transcriptional association networks. The aim of this second method is to apply the information encoded in gene networks for prognostic purpose which is one of the crucial objectives of systems biomedicine. © 2016 - IOS Press and the authors. All rights reserved.

Munoz M.,University of Seville | Rosso M.,University of Seville | Covenas R.,Institute of Neurosciences of Castilla Y Leon INCYL
Current Medicinal Chemistry | Year: 2010

The past two decades have witnessed an exponential increase in research into cancer. This effort, however, has not been translated into better perspectives as regards the problem, although several fields of research have certainly been promising (the human genome project, gene therapy, the search for new cytostatic agents and stem cell research). New pathways must be opened up to offer future hope to oncologic patients. Thus, there is a need to explore other research initiatives in cancer ways to improve this chronic global problem. Substance P (SP) has a widespread distribution in both the central and peripheral nervous systems. It is known that after binding to the specific neurokinin-1 (NK-1) receptor, SP regulates biological functions related to cancer, such as tumour cell proliferation, angiogenesis, and migration of the tumour cells for invasion and metastasis. By contrast, it is also known that after binding to NK-1 receptors, the NK-1 receptor antagonists specifically inhibit tumour cell proliferation (tumour cells die by apoptosis), angiogenesis and the migration of the tumour cells. It is also known that NK-1 receptors are overexpressed in tumours. All these observations suggest that the SP/NK-1 receptor system could play an important role in the development of cancer and metastasis; that the NK-1 receptor could be a new promising target in the treatment of cancer, and that NK-1 receptor antagonists could improve cancer treatment. © 2010 Bentham Science Publishers Ltd.

Herrera M.D.,University of Seville | Mingorance C.,University of Seville | Rodriguez-Rodriguez R.,University of Seville | Alvarez de Sotomayor M.,University of Seville
Ageing Research Reviews | Year: 2010

Aging is an important risk factor for the development of many cardiovascular diseases as atherosclerosis and hypertension with a common underlying circumstance: the progressive decline of endothelial function. Vascular endothelial dysfunction occurs during the human aging process and is accompanied by deterioration in the balance between vasodilator and vasoconstriction substances produced by the endothelium. This imbalance is mainly characterized by a progressive reduction of the bioavailability of nitric oxide (NO) and an increase in the production of cyclooxygenase (COX)-derived vasoconstrictor factors. Both circumstances are in turn related to an increased production of reactive oxygen and nitrogen species. The aim of this review is to describe the pathophysiological mechanisms involved in the endothelial function declination that accompanies the multifactorial aging process, including alterations related to oxidative stress and pro-inflammatory cytokines, senescence of endothelial cells and genetic factors. © 2009 Elsevier Ireland Ltd. All rights reserved.

Lopez-Lazaro M.,University of Seville
Molecular Medicine | Year: 2010

During the last few decades, cancer research has focused on the idea that cancer is caused by genetic alterations and that this disease can be treated by reversing or targeting these alterations. The small variations in cancer mortality observed during the previous 30 years indicate, however, that the clinical applications of this approach have been very limited so far. The development of future gene-based therapies that may have a major impact on cancer mortality may be compromised by the high number and variability of genetic alterations recently found in human tumors. This article reviews evidence that tumor cells, in addition to acquiring a complex array of genetic changes, develop an alteration in the metabolism of oxygen. Although both changes play an essential role in carcinogenesis, the altered oxygen metabolism of cancer cells is not subject to the high genetic variability of tumors and may therefore be a more reliable target for cancer therapy. The utility of this novel approach for the development of therapies that selectively target tumor cells is discussed. © 2010 The Feinstein Institute for Medical Research.

Valverde J.M.,University of Seville
Contemporary Physics | Year: 2015

Chemical and metallurgical processes enhanced by high intensity acoustic waves, thermoacoustic engines and refrigerators, fuel rods in nuclear reactors, heat exchanger tubes, offshore and vibrating structures, solar thermal collectors, acoustic levitators, microfluidic devices, cycling, musical acoustics, blood flow through veins/arteries, hearing in the mammalian ear, carbon nanotube loudspeakers, etc. The evolution of a myriad of processes involving the oscillation of viscous fluids in the presence of solid boundaries is up to a certain extent influenced by acoustic streaming. In addition to the sound field, viscous energy dissipation at the fluid–solid boundary causes a time-independent fluid circulation, which can lead to a significant enhancement of heat, mass and momentum transfer at large oscillation amplitudes. A particularly relevant phenomenon that can be notably affected by acoustic streaming is the promotion of sound waves by temperature gradients or viceversa (thermoacoustics), which is at the basis of potentially efficient and environmental friendly engines and refrigerators that have attracted a renewed interest in the last years. In the present manuscript, historical developments and the underlying basic physics behind acoustic streaming and thermoacoustics are reviewed from an unifying perspective. © 2015 Taylor & Francis.

Sollier J.,Stanford University | Stork C.T.,Stanford University | Garcia-Rubio M.L.,University of Seville | Paulsen R.D.,Stanford University | And 2 more authors.
Molecular Cell | Year: 2014

R-loops, consisting of an RNA-DNA hybrid and displaced single-stranded DNA, are physiological structures that regulate various cellular processes occurring on chromatin. Intriguingly, changes in R-loop dynamics have also been associated with DNA damage accumulation and genome instability; however, the mechanisms underlying R-loop-induced DNA damage remain unknown. Here we demonstrate in human cells that R-loops induced by the absence ofdiverse RNA processing factors, including the RNA/DNA helicases Aquarius (AQR) and Senataxin (SETX), or by the inhibition of topoisomerase I, are actively processed into DNA double-strand breaks (DSBs) by the nucleotide excision repair endonucleases XPF and XPG. Surprisingly, DSB formation requires the transcription-coupled nucleotide excision repair (TC-NER) factor Cockayne syndrome group B (CSB), but not the global genome repair protein XPC. These findings reveal an unexpected and potentially deleterious role for TC-NER factors in driving R-loop-induced DNA damage and genome instability. © 2014 Elsevier Inc.

Covenas R.,University of Salamanca | Munoz M.,University of Seville
Histology and Histopathology | Year: 2014

The substance P (SP)/neurokinin (NK)-1 receptor system plays an important role in cancer. After binding to the NK-1 receptor, SP induces tumor cell proliferation, migration of tumor cells (invasion, infiltration and metastasis) and angiogenesis. In contrast, NK-1 receptor antagonists inhibit tumor cell proliferation (tumor cells die by apoptosis), block the migratory activity of tumor cells, and exert antiangiogenic properties. The induction of apoptosis offers an appropriate method for cancer treatment. The NK-1 receptor can be considered as a target in cancer treatment. A common mechanism for cancer cell proliferation mediated by SP and the NK-1 receptor occurs and NK-1 receptor antagonists are broadspectrum antineoplastic drugs. The NK-1 receptor antagonist aprepitant is used in clinical practice and exerts an antitumor action against a large number of different human tumor cells. In the future, such antitumor action should be tested in human clinical trials.

Justo J.L.,University of Seville | Vazquez M.,University of Seville
Unsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils | Year: 2011

The presence of water in the intergranular voids of partially saturated soils generates a capillary pressure between the grains. This pressure becomes zero for completely dry or saturated conditions. A model for capillary pressure in unsaturated granular soils within the pendular saturation regime has been presented. The model assumes spherical granular surfaces, zero contact angle, grain size <2.7 mm and dominant capillarity (Bond number, Bo<1). The model has been developed for packing of spheres with e=0.35 and e=0.91. The model and experimental results found in the literature have been compared. © 2011 Taylor & Francis Group, London.

Castro-Mendez A.,University of Seville | Munuera P.V.,University of Seville | Albornoz-Cabello M.,University of Seville
Prosthetics and Orthotics International | Year: 2013

Study design: randomized, double-blinded, clinical trial. Background: Low back pain is one of the commonest disorders affecting the back. The literature reflects how over time excessive pronation of the foot has become to be recognized as linked to chronic low back pain, and how the problem can evolve for the better with the use of compensating foot orthoses. Objectives: The main objective of this study is to answer the question of whether the use of a certain type of custommade foot orthosis alleviates low back pain. Material and methods: In a sample of 51 participants with excessive subtalar pronation and chronic low back pain (43 women and 8 men), the effect of custom-made foot orthoses in low back pain was studied. The study design was a randomized, double-blinded, clinical trial with two groups: experimental, treated with the custom-made foot orthoses, and control, treated with a placebo. Low back pain was evaluated by a visual analog scale for pain and Oswestry's Disability Index Questionnaire for lower back pain at two moments-on the day of inclusion in the study and after 4 weeks of treatment. Results: The evolution of the low back pain showed significant differences in the experimental group, showing a significant reduction of pain and disability (p < 0.001, visual analog scale; p < 0.001, Oswestry's Index). Conclusions: In the sample studied, the use of custom-made foot orthoses to control foot pronation had a short-term effect in reduction of perceived low back pain. © The International Society for Prosthetics and Orthotics 2012.

Babiano R.,University of Seville | Gamalinda M.,Carnegie Mellon University | Woolford J.L.,Carnegie Mellon University | de la Cruz J.,University of Seville
Molecular and Cellular Biology | Year: 2012

Ribosomal proteins play important roles in ribosome biogenesis and function. Here, we study the evolutionarily conserved L26 in Saccharomyces cerevisiae, which assembles into pre-60S ribosomal particles in the nucle(ol)us. Yeast L26 is one of the many ribosomal proteins encoded by two functional genes. We have disrupted both genes; surprisingly, the growth of the resulting rpl26 null mutant is apparently identical to that of the isogenic wild-type strain. The absence of L26 minimally alters 60S ribosomal subunit biogenesis. Polysome analysis revealed the appearance of half-mers. Analysis of pre-rRNA processing indicated that L26 is mainly required to optimize 27S pre-rRNA maturation, without which the release of pre-60S particles from the nucle-(ol)us is partially impaired. Ribosomes lacking L26 exhibit differential reactivity to dimethylsulfate in domain I of 25S/5.8S rRNAs but apparently are able to support translation in vivo with wild-type accuracy. The bacterial homologue of yeast L26, L24, is a primary rRNA binding protein required for 50S ribosomal subunit assembly in vitro and in vivo. Our results underscore potential differences between prokaryotic and eukaryotic ribosome assembly. We discuss the reasons why yeast L26 plays such an apparently nonessential role in the cell. © 2012, American Society for Microbiology.

Rosa Diaz I.M.,University of Seville
International Journal of Consumer Studies | Year: 2013

Among the numerous factors that influence decisions on prices, consumer behaviour has special significance. This paper reviews and analyses relevant studies conducted during the last few decades. On the basis of our analysis, four categories of factors that determine consumer behaviour have been identified. Additionally, we have developed an experimental research design to analyse the influence that the following factors have on price perception: price structure (i.e. price level, order of presentation and price differences), purchase context (i.e. reason for purchase or product use) and demographic characteristics (i.e. gender). Results reveal a significant influence of these variables on consumer behaviour. © 2011 Blackwell Publishing Ltd.

Muro-Pastor A.M.,University of Seville | Hess W.R.,Albert Ludwigs University of Freiburg
Trends in Microbiology | Year: 2012

There are several instances of cellular differentiation in prokaryotes, including the formation of spores in Bacillus, the fruiting bodies of Myxococcus, and the stalked cells of Caulobacter. The vegetative cells of particular filamentous cyanobacteria can differentiate into three different cell types: N2-fixing heterocysts, spore-like akinetes, and motile hormogonia. Heterocysts are crucial for the ability of these photosynthetic bacteria to fix N2 because they keep the oxygen-labile nitrogenase away from the photosynthetically produced O2. Heterocysts are morphologically and functionally distinct from vegetative cells in the filament. Their differentiation relies on sophisticated intercellular communication and is tightly regulated. Analyzed by classical mutagenesis for decades, heterocyst differentiation is now being approached by large-scale methodologies, leading to the identification of new elements that might be important in the process. © 2012 Elsevier Ltd.

Aldaz S.,University of Cambridge | Escudero L.M.,University of Cambridge | Escudero L.M.,University of Seville | Freeman M.,University of Cambridge
Nature Communications | Year: 2013

The motor protein non-muscle myosin II is a major driver of the movements that sculpt three-dimensional organs from two-dimensional epithelia. The machinery of morphogenesis is well established but the logic of its control remains unclear in complex organs. Here we use live imaging and ex vivo culture to report a dual role of myosin II in regulating the development of the Drosophila wing. First, myosin II drives the contraction of a ring of cells that surround the squamous peripodial epithelium, providing the force to fold the whole disc through about 90. Second, myosin II is needed to allow the squamous cells to expand and then retract at the end of eversion. The combination of genetics and live imaging allows us to describe and understand the tissue dynamics, and the logic of force generation needed to transform a relatively simple imaginal disc into a more complex and three-dimensional adult wing. © 2013 Macmillan Publishers Limited. All rights reserved.

Romero-Gomez M.,University of Seville
Expert Opinion on Pharmacotherapy | Year: 2010

Importance of the field: Hepatic encephalopathy (HE) is a major complication encountered in nearly half of the patients with liver cirrhosis. Areas covered in this review: A review of the safety and efficacy of current therapies for HE that seek to pre-empt ammonia production and/or to increase its elimination, reducing inflammation, blocking benzodiazepine-like compound production, and supporting systemic hemodynamics. What the reader will gain: Insight into some recent advances in the management of HE that could modify our therapeutic approach to end-stage liver disease. Cirrhotic individuals during an overt HE episode require careful management, focusing on precipitant factors as well as metabolic and hemodynamic derangements. Take home message: Intestinal ammoniagenesis requires flora modification by antibiotics, prebiotics and probiotics; glutaminase inhibition as well as antibiotics to pre-empt systemic inflammation. Hemodynamic/fluid support is essential. Nutritional support is crucial and hypoproteinemic diets should be avoided. Blocking benzodiazepine-like compounds by the use of flumazenil could be useful in patients with severe, benzodiazepine-induced HE. Long-term rifaximin is well tolerated, does not promote resistance and could decrease overt HE bouts in patients with previous episodes of overt HE. Lactulose is better than no treatment in improving quality of life in patients with minimal HE; it also acts as secondary prophylaxis following overt HE. © 2010 Informa UK Ltd.

D'Hulst C.,Lille University of Science and Technology | Merida A.,University of Seville
New Phytologist | Year: 2010

Starch is the main polymer in which carbon and energy are stored in land plants, algae and some cyanobacteria. It plays a crucial role in the physiology of these organisms and also represents an important polymer for humans, in terms of both diet and nonfood industry uses. Recent efforts have elucidated most of the steps involved in the synthesis of starch. However, the process that initiates the synthesis of the starch granule remains unclear. Here, we outline the similarities between the synthesis of starch and the synthesis of glycogen, the other widespread and abundant glucose-based polymer in living cells. We place special emphasis on the mechanisms of initiation of the glycogen granule and current knowledge concerning the initiation of the starch granule. We also discuss recent discoveries regarding the function of starch synthases in the priming of the starch granule and possible interactions with other elements of the starch synthesis machinery. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).

Guevorkian K.,University Pierre and Marie Curie | Colbert M.-J.,McMaster University | Durth M.,Ecole Polytechnique - Palaiseau | Durth M.,University of Seville | And 2 more authors.
Physical Review Letters | Year: 2010

Spherical cellular aggregates are in vitro systems to study the physical and biophysical properties of tissues. We present a novel approach to characterize the mechanical properties of cellular aggregates using a micropipette aspiration technique. We observe an aspiration in two distinct regimes: a fast elastic deformation followed by a viscous flow. We develop a model based on this viscoelastic behavior to deduce the surface tension, viscosity, and elastic modulus. A major result is the increase of the surface tension with the applied force, interpreted as an effect of cellular mechanosensing. © 2010 The American Physical Society.

Cabello A.,University of Seville
Physical Review Letters | Year: 2010

Two distant systems can exhibit quantum nonlocality even though the correlations between them admit a local model. This nonlocality can be revealed by testing extra correlations between successive measurements on one of the systems which do not admit a noncontextual model whatever the reduced state of this system is. This shows that quantum contextuality plays a fundamental role in quantum nonlocality, and allows an experimental test of the Kochen-Specker with locality theorem. © 2010 The American Physical Society.

Becerro A.I.,University of Seville | Rodriguez-Liviano S.,University of Seville | Fernandez-Carrion A.J.,University of Seville | Ocana M.,University of Seville
Crystal Growth and Design | Year: 2013

Homogeneous monoclinic GdPO4 particles composed of three intersecting lance-shaped crystals forming a penetration twin have been synthesized following a very restrictive, simple, and fast (10 min) method consisting of the hydrothermal reaction of gadolinium acetylacetonate with H3PO4 in a mixture of ethylene glycol and water at 180 C. Slightly increasing the amount of water in the solvent mixture leads to hexagonal rodlike GdPO4·0.5H2O nanoparticles, whereas the variation of the Gd source, PO4 source, aging temperature, and polyol type gave rise to heterogeneous particles. The synthesis procedure is also suitable for the preparation of Eu3+-, Tb 3+-, and Dy3+-doped GdPO4 particles with the same morphology and crystalline structure as the undoped materials. The effect of the doping level on the luminescent properties of the twinlike nanophosphors was evaluated, finding optimum doping levels of 5, 5, and 1% for the Eu 3+-, Tb3+-, and Dy3+-doped materials, respectively. The twinlike GdPO4 nanophosphors were found to be more efficient than the rodlike GdPO4 ones in terms of emission intensity. Finally, a solid-state single-phase white-light-emitting nanophosphor has been fabricated for the first time in this system by triply doping the GdPO 4 twined particles with appropriate concentrations of Eu 3+, Tb3+, and Dy3+ and exciting through the Gd-Ln energy-transfer band at 273 nm. In addition to this energy transfer band, other energy charge transfer processes among the three dopants (Eu3+, Tb3+, and Dy3+) have been observed in the triply doped material. © 2012 American Chemical Society.

Gambadauro P.,Uppsala University Hospital | Torrejon R.,University of Seville
Surgery Today | Year: 2013

New technological developments in the field of telecommunications have allowed a wide range of potentially novel surgical applications. The introduction of the World Wide Web in 1991 has been followed by a steep rise of the relevance of telemedicine, as it is witnessed in the latest scientific literature. There has been a consistent, positive trend in publications dealing, respectively, with telemedicine and the Internet. This article reviews telemedicine and other surgery-related innovations that benefit from telecommunication advances, and presents data from a quantitative bibliographic analysis. A number of applications, such as telementoring, teleproctoring and robotic telesurgery are described and their huge potentials are discussed. The integration between surgery and telecommunications could constitute one of the major achievements of modern medicine, and its safe integration into clinical practice should be a priority for modern surgeons. © 2012 Springer.

Cancers of unknown primary site are metastatic cancers for which primary tumors are not found after detailed investigations. In many cases, the site of origin is not identified even on postmortem examination. These cancers are the fourth most common cause of cancer death. The biological events involved in the development of this type of cancers remain unknown. This manuscript discusses that, like metastatic cells, stem cells have a natural ability to migrate. A cancer of unknown primary site would form when deregulated, premalignant or cancerous stem cells migrated away from their natural tissue and gave rise to a cancer in a new site before or without generating a tumor in their original tissue. It is important to realize that forming a tumor in a tissue is not a prerequisite for stem cells to migrate away from that tissue. This view is in accordance with recent observations that strongly support the tumorigenesis model in which cancer arises from normal stem cells. Evidence has accumulated that cancer stem cells may play a key role in cancer progression and resistance to therapy. Successful treatment of cancer, including that of unknown primary site, may therefore require the development of therapies against cancer stem cells.

Gomez-Estern F.,University of Seville | Canudas-De-Wit C.,French National Center for Scientific Research | Rubio F.R.,University of Seville
IEEE Transactions on Automatic Control | Year: 2011

This technical note investigates the closed-loop properties of the differential coding scheme known as Delta Modulation (Δ - M) when used in feedback loops within the context of linear systems controlled through a communication network. We propose a new adaptive scheme with variable quantization step Δ, by defining an adaptation law exclusively in terms of information available at both the transmitter and receiver. With this approach, global asymptotic stability of the networked control system is achieved for a class of controllable (possibly unstable) linear plants. Moreover, thanks to the globally defined switching policy, this architecture enjoys a disturbance rejection property that allows the system to recover from any finite-time unbounded disturbance or communication loss. © 2010 IEEE.

McConnell M.J.,University of Seville | Pachon J.,University of Seville
Vaccine | Year: 2010

The treatment of infections caused by Acinetobacter baumannii has become increasingly complicated due to the emergence of highly resistant strains. In the present study we demonstrate that immunization with an inactivated whole cell vaccine elicits a robust antibody response that provides protection against challenge with multiple A. baumannii strains in a murine model of disseminated sepsis. In addition, we show that passive immunization with serum raised against inactivated cells protects mice from subsequent infection. These results demonstrate that active and passive immunization using an inactivated whole cell vaccine may be an effective approach for preventing infection by A. baumannii. © 2010 Elsevier Ltd.

Stuckey R.,University of Seville | Garcia-Rodriguez N.,University of Seville | Aguilera A.,University of Seville | Wellinger R.E.,University of Seville
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015

DNA replication initiates at defined replication origins along eukaryotic chromosomes, ensuring complete genome duplication within a single S-phase. A key feature of replication origins is their ability to control the onset of DNA synthesis mediated by DNA polymerase-α and its intrinsic RNA primase activity. Here, we describe a novel origin-independent replication process that is mediated by transcription. RNA polymerase I transcription constraints lead to persistent RNA:DNA hybrids (R-loops) that prime replication in the ribosomal DNA locus. Our results suggest that eukaryotic genomes have developed tools to prevent R-loop-mediated replication events that potentially contribute to copy number variation, particularly relevant to carcinogenesis. © 2015, National Academy of Sciences. All rights reserved.

Objectives:Treatment for celiac disease (CD) is a lifelong strict gluten-free diet (GFD). Patients should be followed-up with dietary interviews and serology as CD markers to ensure adherence to the diet. However, none of these methods offer an accurate measure of dietary compliance. Our aim was to evaluate the measurement of gluten immunogenic peptides (GIP) in stools as a marker of GFD adherence in CD patients and compare it with traditional methods of GFD monitoring.Methods:We performed a prospective, nonrandomized, multicenter study including 188 CD patients on GFD and 84 healthy controls. Subjects were given a dietary questionnaire and fecal GIP quantified by enzyme-linked immunosorbent assay (ELISA). Serological anti-tissue transglutaminase (anti-tTG) IgA and anti-deamidated gliadin peptide (anti-DGP) IgA antibodies were measured simultaneously.Results:Of the 188 celiac patients, 56 (29.8%) had detectable GIP levels in stools. There was significant association between age and GIP in stools that revealed increasing dietary transgressions with advancing age (39.2% in subjects ≥13 years old) and with gender in certain age groups (60% in men ≥13 years old). No association was found between fecal GIP and dietary questionnaire or anti-tTG antibodies. However, association was detected between GIP and anti-DGP antibodies, although 46 of the 53 GIP stool-positive patients were negative for anti-DGP.Conclusions:Detection of gluten peptides in stools reveals limitations of traditional methods for monitoring GFD in celiac patients. The GIP ELISA enables direct and quantitative assessment of gluten exposure early after ingestion and could aid in the diagnosis and clinical management of nonresponsive CD and refractory CD. Trial registration number NCT02711397.Am J Gastroenterol advance online publication, 20 September 2016; doi:10.1038/ajg.2016.439. © 2016 American College of Gastroenterology

Amaro J.E.,University of Granada | Barbaro M.B.,University of Turin | Caballero J.A.,University of Seville | Donnelly T.W.,Massachusetts Institute of Technology | Williamson C.F.,Massachusetts Institute of Technology
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

We evaluate the quasielastic double differential neutrino cross sections obtained in a phenomenological model based on the superscaling behavior of electron scattering data. We compare our results with the recent experimental data for neutrinos of MiniBooNE and estimate the contribution of the vector meson-exchange currents in the 2p-2h sector. © 2010 Elsevier B.V.

Quintana F.J.,Harvard University | Farez M.F.,Harvard University | Izquierdo G.,University of Seville | Lucas M.,University of Seville | And 2 more authors.
Neurology | Year: 2012

Objective: Multiple sclerosis (MS) is characterized by the local production of antibodies in the CNS and the presence of oligoclonal bands in the CSF. Antigen arrays allow the study of antibody reactivity against a large number of antigens using small volumes of fluid with greater sensitivity than ELISA. We investigated whether there were unique autoantibodies in the CSF of patients with MS as measured by antigen arrays and whether these antibodies differed from those in serum. Methods: We used antigen arrays to analyze the reactivity of antibodies in matched serum and CSF samples of 20 patients with untreated relapsing-remitting MS (RRMS), 26 methylprednisolone-treated patients with RRMS, and 20 control patients with other noninflammatory neurologic conditions (ONDs) against 334 different antigens including heat shock proteins, lipids, and myelin antigens. Results: We found different antibody signatures in matched CSF and serum samples The targets of these antibodies included epitopes of the myelin antigens CNP, MBP, MOBP, MOG, and PLP (59%), HSP60 and HSP70 (38%), and the 68-kD neurofilament (3%). The antibody response in patients with MS was heterogeneous; CSF antibodies in individual patients reacted with different autoantigens. These autoantibodies were locally synthesized in the CNS and were of the immunoglobulin G class. Finally, we found that treatment with steroids decreased autoantibody reactivity, epitope spreading, and intrathecal autoantibody synthesis. Conclusions: These studies provide a new avenue to investigate the local antibody response in the CNS, which may serve as a biomarker to monitor both disease progression and response to therapy in MS. Copyright © 2012 by AAN Enterprises, Inc.

Carrizosa E.,University of Seville | Guerrero V.,University of Seville
Computers and Operations Research | Year: 2013

Principal component analysis is a popular data analysis dimensionality reduction technique, aiming to project with minimum error for a given dataset into a subspace of smaller number of dimensions. In order to improve interpretability, different variants of the method have been proposed in the literature, in which, besides error minimization, sparsity is sought. In this paper we formulate as a mixed integer nonlinear program the problem of finding a subspace with a sparse basis minimizing the sum of squares of distances between the points and their projections. Contrary to other attempts in the literature, with our model the user can fix the level of sparseness of the resulting basis vectors. Variable neighborhood search is proposed to solve the problem obtained this way. Our numerical experience on test sets shows that our procedure outperforms benchmark methods in the literature, both in terms of sparsity and errors. © 2013 Elsevier Ltd. All rights reserved.

Sanchez-Fidalgo S.,University of Seville | Cardeno A.,University of Seville | Sanchez-Hidalgo M.,University of Seville | Aparicio-Soto M.,University of Seville | De la Lastra C.A.,University of Seville
Journal of Nutritional Biochemistry | Year: 2013

We evaluated the protective effect of dietary extra virgin olive oil (EVOO) polyphenol extract (PE) supplementation in the inflammatory response associated to chronic colitis model. Six-week-old mice were randomized in four dietary groups: standard diet (SD), EVOO diet and both enriched with PE (850 ppm) (SD+PE and EVOO+PE). After 30 days, animals that were exposed to dextran sodium sulfate (DSS) (3%) followed by 3 weeks of drinking water developed chronic colitis, which was evaluated by disease activity index (DAI) and histology. Cell proliferation was analyzed by immunohistochemical and changes in monocyte chemotactic protein (MCP)-1 and tumor necrosis factor (TNF)-α mRNA expression by quantitative real-time polymerase chain reaction. Colonic expression of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, mitogen-activated protein kinases (MAPKs), IκBα inhibitory and peroxisome proliferator-activated receptor gamma (PPARγ) were determined by western blotting. SD-DSS group showed a significant increase of DAI, histological damage and cell proliferation, as well as an up-regulation of TNF-α, MCP-1, COX-2 and iNOS proteins. p38 and JNK MAPKs phosphorylation, IκBα degradation and PPARγ deactivation were also observed. However, in DSS-treated and EVOO+PE-fed mice, DAI and cell proliferation were significantly reduced, as well as MCP-1, TNF-α, COX-2 and iNOS expression levels. In addition, this dietary group, notably down-regulated JNK phosphorylation, prevented IκBα degradation and PPARγ deactivation. These results demonstrated, for the first time, that EVOO-PE supplementation possessed marked protective effects on experimental colitis through PPARγ up-regulation and nuclear transcription factor-kappa B and MAPK signaling pathway inhibition, decreasing the inflammatory cascade. We concluded that PE-enriched EVOO diet could be a beneficial functional food on ulcerative colitis. © 2013 Elsevier Inc.

Carrizosa E.,University of Seville | Romero Morales D.,University of Oxford
Computers and Operations Research | Year: 2013

Data mining techniques often ask for the resolution of optimization problems. Supervised classification, and, in particular, support vector machines, can be seen as a paradigmatic instance. In this paper, some links between mathematical optimization methods and supervised classification are emphasized. It is shown that many different areas of mathematical optimization play a central role in off-the-shelf supervised classification methods. Moreover, mathematical optimization turns out to be extremely useful to address important issues in classification, such as identifying relevant variables, improving the interpretability of classifiers or dealing with vagueness/noise in the data. © 2012 Elsevier Ltd. All rights reserved.

Mesa J.A.,University of Seville | Ortega F.A.,University of Seville | Pozo M.A.,University of Seville
Computers and Operations Research | Year: 2013

Railway systems in metropolitan areas carry a high density of traffic daily, heterogeneously distributed, and exposed to the negative consequences derived from service disruptions. An interesting topic in the literature is to obtain performance protocols in the presence of contingencies which can affect the system operation, avoiding the propagation of perturbation and minimizing its consequences. The objective of this paper is to assess the decision of rescheduling the train service, reducing the current supply along one transportation line in order to reinforce the service of another line, exploited by the same public operator, which has suffered an incidence or emergency. A methodology, based on a geometric representation of solutions which allows the use of discrete optimization techniques, is developed in order to attend to the underlying demand with efficiency criteria in this context of unexpected incidents. © 2011 Elsevier Ltd.

Current approaches to assessing preclinical anticancer activity do not reliably predict drug efficacy in cancer patients. Most of the compounds that show remarkable anticancer effects in preclinical models actually fail when tested in clinical trials. We blame these failures on the complexity of the disease and on the limitations of the preclinical tools we require for our research. This manuscript argues that this lack of clinical response may also be caused by poor in vitro and in vivo preclinical designs, in which cancer patients' needs are not fully considered. Then, it proposes two patientoriented tests to assess in vitro and in vivo anticancer activity and to help validate drug candidates for clinical evaluation.

Rozas J.L.,University of Seville
Advances in Experimental Medicine and Biology | Year: 2011

Kainate receptors are widely distributed in the CNS, but also in the PNS. Dorsal root ganglia are enriched in this subtype of glutamate ionotropic receptors. In addition to their activity as ligand-gated ion channels, kainate receptors exhibit other properties already characterized in other systems, such as hippocampus, i.e., their ability to induce a metabotropic cascade signalling, through G-protein and PKC activation. With a very similar actuation mechanism as formerly described in the CNS, kainate receptors in the DRG also present other differentiated features, such as the Ca 2+ channel blockade and a self-regulation property. The peculiarity of these neurons has served to progress the study of kainate receptors. Nevertheless, many other physiological functions of these receptors remain unclear, as does the related molecular nature of the metabotropic cascade and the involvement of this signalling pathway with sensory transmission of pain. © 2011 Landes Bioscience and Springer Science+Business Media, LLC.

Frejo J.R.D.,University of Seville | Camacho E.F.,University of Seville
IEEE Transactions on Intelligent Transportation Systems | Year: 2012

This paper compares global and local model predictive control (MPC) algorithms in a traffic network controlled by intelligent transportation system (ITS) signals (ramp metering and variable speed limits). It will be shown that local techniques have a suboptimal behavior and that centralized techniques are difficult to implement in real time. To deal with this problem, a local MPC with only one communication cycle at each sampling time is proposed. This controller improves the local controller performance, and although it is suboptimal with regard to the centralized controller behavior, it can be implemented in real time. © 2011 IEEE.

Gallego A.J.,University of Seville | Camacho E.F.,University of Seville
Control Engineering Practice | Year: 2012

Model Predictive control algorithms for trough solar plants make use of solar radiation measurements and the overall efficiency knowledge which are very useful in order to reject disturbances. However, direct solar radiation, mirror reflectivity and metal absorptance which affect overall efficiency, can only be measured locally. In this paper, an adaptative model predictive control using an unscented Kalman filter (UKF) to estimate both the effective solar radiation and the metal-fluid temperature profiles is proposed. The control algorithm is validated by tests with real data taken from the ACUREX field of the PSA in Almería (Spain). © 2012 Elsevier Ltd.

Arzac G.M.,University of Seville | Rojas T.C.,University of Seville | Fernandez A.,University of Seville
ChemCatChem | Year: 2011

Co{dot operator}B-based materials are widely used as catalysts for hydrogen generation through sodium borohydride self-decomposition. In the mid 1990s, the aqueous and organic chemistry involved in Co{dot operator}B synthesis and handling was studied. Nevertheless, the exact microstructure of these catalysts has remained unsolved. Herein we present an exhaustive study which shows a new and complete microstructural view of a Co{dot operator}B-based material together with the chemistry of the cobalt and boron involved. By using nanoscale-resolution microscopy and spectroscopy techniques, we have elucidated the role of boron compounds as stabilizers in a complex microstructure, which also explains its high catalytic performance and long-term stability. The catalyst is proposed to be made up of 1-3nm hcp Co0 nanoparticles embedded in amorphous CoxB (x=1, 2, 3), CoxOy, Co(BO2)2, and B2O3 phases alternatively or all together. All of these amorphous phases protect the nanocrystalline metallic core from growth and oxidation. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gonzalez-Prida V.,General Dynamics Corporation | Crespo Marquez A.,University of Seville
Computers in Industry | Year: 2012

The objective of this paper is to suggest a management framework for a better organization of warranty assistance, using engineering techniques already developed for similar processes and according to a process-based quality management system. Therefore, a generic framework is presented that integrates management methodologies which will be gathered in four sequential steps, where each different technique will play a crucial role. Following this scheme, a supporting framework for the management of a warranty program is defined. This offers a practical vision of the set of activities that each warranty management process consists of and focuses on the relationship between manufacturer and user. By reengineering managerial processes and/or by the application of a correct warranty management system it is possible to have a greater influence on product design and manufacturing, increasing product quality by sharing and boosting the information flow about product defects, their sources and possible solutions. The result of the study is, in short, a classification of different engineering tools, focused mainly on warranty and product management. In addition to this it also demonstrates how aspects of maintenance and manufacturing can be enhanced before finally discussing briefly the proper use of each tool according to the available data or information. All this is illustrated through a comprehensive representation that will help the reader to understand in a practical way, the different information inputs/outputs among the proposed steps. © 2012 Elsevier B.V.

Rodriguez-Gomez J.A.,University of Seville | Levitsky K.L.,University of Seville | Lopez-Barneo J.,University of Seville
American Journal of Physiology - Cell Physiology | Year: 2012

Ion channels participate in cell homeostasis and are involved in the regulation of proliferation and differentiation in several cell types; however, their presence and function in embryonic stem (ES) cells are poorly studied. We have investigated the existence of voltage-dependent inward currents in mouse ES cells and their ability to modulate proliferation and selfrenewal. Patch-clamped ES cells had inactivating tetrodotoxin (TTX)-sensitive Na + currents as well as transient Ca 2+ currents abolished by the external application of Ni 2+. Biophysical and pharmacological data indicated that the Ca 2+ current is predominantly mediated by T-type (Cav3 v2) channels. The number of cells expressing T-type channels and Cav3 v2 mRNA levels increased at the G1/S transition of the cell cycle. TTX had no effect on ES cell proliferation. However, blockade of T-type Ca 2+ currents with Ni 2+ induced a decrease in proliferation and alkaline phosphatase positive colonies as well as reduced expression of Oct3/4 and Nanog, all indicative of loss in self-renewal capacity. Decreased alkaline phosphatase and Oct3/4 expression were also observed in cells subjected to small interfering RNA-induced knockdown for T-type (Cav3 v2) Ca 2+ channels, thus partially recapitulating the pharmacological effects on self-renewal. These results indicate that Cav3 v2 channel expression in ES cells is modulated along the cell cycle being induced at late G1 phase. They also suggest that these channels are involved in the maintenance of the undifferentiated state of mouse ES cells. We propose that Ca 2+ entry mediated by Cav3 v2 channels might be one of the intracellular signals that participate in the complex network responsible for ES cell self-renewal. © 2012 the American Physiological Society.

Garcia-Rubio M.L.,University of Seville | Aguilera A.,University of Seville
Nucleic Acids Research | Year: 2012

Despite the theoretical bases for the association of topoisomerases and supercoiling changes with transcription and replication, our knowledge of the impact of topological constraints on transcription and replication is incomplete. Although mutation of topoisomerases affects expression and stability of the rDNA region it is not clear whether the same is the case for RNAPII transcription and genome integrity in other regions. We developed new assays in which two convergent RNAPII-driven genes are transcribed simultaneously. Plasmid-based systems were constructed with and without a transcription terminator between the two convergent transcription units, so that the impact of transcription interference could also be evaluated. Using these assays we show that Topos I and II play roles in RNAPII transcription in vivo and reduce the stability of RNAPII-transcribed genes in Saccharomyces cerevisiae. Supercoiling accumulation in convergent transcription units impairs RNAPII transcription in top1Δ strains, but Topo II is also required for efficient transcription independent of Topo I and of detectable supercoiling accumulation. Our work shows that topological constraints negatively affect RNAPII transcription and genetic integrity, and provides an assay to study gene regulation by transcription interference. © 2011 The Author(s).

Groth P.,University of Stockholm | Groth P.,A-Life Medical | Orta M.L.,University of Seville | Elvers I.,University of Stockholm | And 3 more authors.
Nucleic Acids Research | Year: 2012

Ionizing radiation (IR) produces direct two-ended DNA double-strand breaks (DSBs) primarily repaired by non-homologous end joining (NHEJ). It is, however, well established that homologous recombination (HR) is induced and required for repair of a subset of DSBs formed following IR. Here, we find that HR induced by IR is drastically reduced when post-DNA damage replication is inhibited in mammalian cells. Both IR-induced RAD51 foci and HR events in the hprt gene are reduced in the presence of replication polymerase inhibitor aphidicolin (APH). Interestingly, we also detect reduced IR-induced toxicity in HR deficient cells when inhibiting post-DNA damage replication. When studying DSB formation following IR exposure, we find that apart from the direct DSBs the treatment also triggers formation of secondary DSBs peaking at 7-9h after exposure. These secondary DSBs are restricted to newly replicated DNA and abolished by inhibiting post-DNA damage replication. Further, we find that IR-induced RAD51 foci are decreased by APH only in cells replicating at the time of IR exposure, suggesting distinct differences between IR-induced HR in S- and G2-phases of the cell cycle. Altogether, our data indicate that secondary replication-associated DSBs formed following exposure to IR are major substrates for IR-induced HR repair. © The Author(s) 2012.

Monge D.,University of Seville | Jiang H.,Lundbeck | Alvarez-Casao Y.,University of Seville
Chemistry - A European Journal | Year: 2015

This Concept article summarizes strategies and developments regarding the use of masked unsaturated esters/amides in asymmetric organocatalysis. Useful substrates are categorized by the design of their inherent carboxylate template. This template group not only enables their functionality as ester surrogates, but also define their accessibilities, modes of interactions with catalysts and the simplicity with which they transform back to the parent carboxylates. Both covalent and noncovalent catalytic systems are discussed and examples showing the entire process (from substrates-to-functionalized ester/ amides) are given. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vaquero-Sedas M.I.,University of Seville | Luo C.,Rutgers University | Vega-Palas M.A.,University of Seville
Nucleic Acids Research | Year: 2012

The chromatin structure of eukaryotic telomeres plays an essential role in telomere functions. However, their study might be impaired by the presence of interstitial telomeric sequences (ITSs), which have a widespread distribution in different model systems. We have developed a simple approach to study the chromatin structure of Arabidopsis telomeres independently of ITSs by analyzing ChIP-seq data. This approach could be used to study the chromatin structure of telomeres in some other eukaryotes. The analysis of ChIP-seq experiments revealed that Arabidopsis telomeres have higher density of histone H3 than centromeres, which might reflects their short nucleosomal organization. These experiments also revealed that Arabidopsis telomeres have lower levels of heterochromatic marks than centromeres (H3K9Me2 and H3K27 Me), higher levels of some euchromatic marks (H3K4Me2 and H3K9Ac) and similar or lower levels of other euchromatic marks (H3K4 Me3, H3K36Me2, H3K36Me3 and H3K18Ac). Interestingly, the ChIP-seq experiments also revealed that Arabidopsis telomeres exhibit high levels of H3K27Me3, a repressive mark that associates with many euchromatic genes. The epigenetic profile of Arabidopsis telomeres is closely related to the previously defined chromatin state 2. This chromatin state is found in 23% of Arabidopsis genes, many of which are repressed or lowly expressed. At least, in part, this scenario is similar in rice. © 2012 The Author(s).

Schaffler I.,University of Bayreuth | Balao F.,University of Seville | Dotterl S.,University of Bayreuth
Annals of Botany | Year: 2012

Background and AimsUnrelated plants pollinated by the same group or guild of animals typically evolve similar floral cues due to pollinator-mediated selection. Related plant species, however, may possess similar cues either as a result of pollinator-mediated selection or as a result of sharing a common ancestor that possessed the same cues or traits. In this study, visual and olfactory floral cues in Lysimachia species exhibiting different pollination strategies were analysed and compared, and the importance of pollinators and phylogeny on the evolution of these floral cues was determined. For comparison, cues of vegetative material were examined where pollinator selection would not be expected.MethodsFloral and vegetative scents and colours in floral oil- and non-floral oil-secreting Lysimachia species were studied by chemical and spectrophotometric analyses, respectively, compared between oil- and non-oil-secreting species, and analysed by phylogenetically controlled methods.Key ResultsVegetative and floral scent was species specific, and variability in floral but not vegetative scent was lower in oil compared with non-oil species. Overall, oil species did not differ in their floral or vegetative scent from non-oil species. However, a correlation was found between oil secretion and six floral scent constituents specific to oil species, whereas the presence of four other floral compounds can be explained by phylogeny. Four of the five analysed oil species had bee-green flowers and the pattern of occurrence of this colour correlated with oil secretion. Non-oil species had different floral colours. The colour of leaves was similar among all species studied.ConclusionsEvidence was found for correlated evolution between secretion of floral oils and floral but not vegetative visual and olfactory cues. The cues correlating with oil secretion were probably selected by Macropis bees, the specialized pollinators of oil-secreting Lysimachia species, and may have evolved in order to attract these bees. © The Author 2012. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.

Castellano-Pozo M.,University of Seville | Garcia-Muse T.,University of Seville | Aguilera A.,University of Seville
EMBO Reports | Year: 2012

R-loops are harmful structures with a negative impact on transcription and recombination during mitosis, but no information exists for meiosis. We used Saccharomyces cerevisiae and Caenorhabditis elegans THO mutants as a tool to determine the consequences of R-loops in meiosis. We found that both S. cerevisiae and C. elegans THO mutants show defective meiosis and an impairment of premeiotic replication as well as DNA-damage accumulation. Importantly, RNase H partially suppressed the replication impairment and the DNA-damage accumulation. We conclude that R-loops can form during meiosis causing replication impairment with deleterious results. © 2012 EUROPEAN MOLECULAR BIOLOGY ORGANIZATION.

Doubova A.,University of Seville | Fernandez-Cara E.,University of Seville
Systems and Control Letters | Year: 2012

This paper is devoted to analyzing the control of vicoelastic fluids of the Jeffreys kind, also known as Oldroyd models. We will present the interesting problems, with special emphasis in the difficulties that they involve. Then, we will consider appropriate linear approximations and we will establish some partial approximate-finite dimensional controllability results in an arbitrarily small time, with distributed or boundary controls supported by arbitrarily small sets. The proofs rely on some specific unique continuation properties which are implied by the structure of the solutions. © 2012 Elsevier B.V. All rights reserved.

Bengoechea C.,University of Seville | Peinado I.,Polytechnic University of Valencia | McClements D.J.,University of Massachusetts Amherst
Food Hydrocolloids | Year: 2011

Lactoferrin is a globular protein from milk that has considerable potential as a functional ingredient in food, cosmetic and pharmaceutical applications. In this study, we examined the possibility of preparing food-grade bovine lactoferrin (bLf) nanoparticles using a simple thermal processing method. Differential Scanning Calorimetry (DSC), light scattering, and ζ-potential techniques were used to provide information about the conformational changes, aggregation, and electrical charge of bLf in aqueous solutions. DSC studies indicated that the protein had two thermal denaturation temperatures (61 and 93 °C), which were associated with two different lobes of the protein. Protein denaturation was found to be irreversible, which was attributed to the formation of protein nanoparticles, whose size depended on the temperature and duration of the thermal treatment. Higher holding temperatures produced faster protein aggregation and larger protein nanoparticles: 85 > 80 > 75 > 70 °C. The protein nanoparticles produced by thermal treatment were resistant to subsequent changes in pH (from 3 to 11) and to salt addition (0-200 mM NaCl). The lactoferrin nanoparticles produced in this study may be useful as function ingredients in commercial products. © 2010 Elsevier Ltd.

Rodriguez D.,University of Alcalá | Ruiz R.,Pablo De Olavide University | Riquelme J.C.,University of Seville | Aguilar-Ruiz J.S.,Pablo De Olavide University
Information Sciences | Year: 2012

Data mining methods in software engineering are becoming increasingly important as they can support several aspects of the software development life-cycle such as quality. In this work, we present a data mining approach to induce rules extracted from static software metrics characterising fault-prone modules. Due to the special characteristics of the defect prediction data (imbalanced, inconsistency, redundancy) not all classification algorithms are capable of dealing with this task conveniently. To deal with these problems, Subgroup Discovery (SD) algorithms can be used to find groups of statistically different data given a property of interest. We propose EDER-SD (Evolutionary Decision Rules for Subgroup Discovery), a SD algorithm based on evolutionary computation that induces rules describing only fault-prone modules. The rules are a well-known model representation that can be easily understood and applied by project managers and quality engineers. Thus, rules can help them to develop software systems that can be justifiably trusted. Contrary to other approaches in SD, our algorithm has the advantage of working with continuous variables as the conditions of the rules are defined using intervals. We describe the rules obtained by applying our algorithm to seven publicly available datasets from the PROMISE repository showing that they are capable of characterising subgroups of fault-prone modules. We also compare our results with three other well known SD algorithms and the EDER-SD algorithm performs well in most cases. © 2011 Elsevier Inc. All rights reserved.

Torres Y.,University of Seville | Pavon J.J.,University of Antioquia | Rodriguez J.A.,University of Seville
Journal of Materials Processing Technology | Year: 2012

Porous samples of commercially pure titanium (CP Ti) were fabricated by using sodium chloride (NaCl) as space-holder with percentages between 40 and 70 vol%. The dissolution of NaCl in distilled water, the structural integrity of samples and the reproducibility of the procedure were studied as a step prior to sintering. All these parameters were evaluated in terms of the compaction pressure, temperature and agitation of water, and dissolution time. The characterization of samples included density, porosity and dynamic Young's modulus. The results indicate that the most efficient lixiviation, according to the desired balance of properties, was by immersion in hot water, without agitation and for prolonged cycles of immersion time. © 2011 Elsevier B.V. All rights reserved.

Liu J.,University of California at Los Angeles | Chen X.,University of California at Los Angeles | De La Pena D.M.,University of Seville | Christofides P.D.,University of California at Los Angeles
IEEE Transactions on Automatic Control | Year: 2012

In this work, we focus on iterative distributed model predictive control (DMPC) of large-scale nonlinear systems subject to asynchronous, delayed state feedback. The motivation for studying this control problem is the presence of asynchronous, delayed measurement samplings in chemical processes and the potential use of networked sensors and actuators in industrial process control applications to improve closed-loop performance. Under the assumption that there exist upper bounds on the time interval between two successive state measurements and on the maximum measurement delay, we design an iterative DMPC scheme for nonlinear systems via Lyapunov-based control techniques. Sufficient conditions under which the proposed distributed MPC design guarantees that the state of the closed-loop system is ultimately bounded in a region that contains the origin are provided. The theoretical results are illustrated through a catalytic alkylation of benzene process example. © 2011 IEEE.

Sanchez-Lafuente A.M.,University of Seville | Rodriguez-Girones M.A.,CSIC - Estación Experimental De Zonas Áridas | Parra R.,University of Seville
Oecologia | Year: 2012

It is widely recognized that pollinators vary in their effectiveness in pollination mutualisms, due both to differences in flower-pollinator morphological fit as well as pollinator behaviour. However, pollination webs typically treat all interactions as equal, and we contend that this method may provide misleading results. Using empirical and theoretical data, we present the case study of a self-incompatible herb in which the number of flowers visited by a pollinator cannot be used as a surrogate for the total effect of a pollinator on a plant due to differences in per-visit effectiveness at producing seeds. In self-incompatible species, the relationship between interaction frequency and per-interaction effect may become increasingly negative as more flowers per plant are visited due to geitonogamous pollen transfer. We found that pollinators making longer bouts (i. e. visiting more flowers per plant visit) had an overall higher pollination success per bout. However, per-interaction effects tended to decrease as the bout progressed, particularly for pollinators that cause higher pollen deposition. Since the same interaction frequency may result from different combinations of number of bouts (plant visits) and bout length (flowers visited/bout), pollinators making repeatedly shorter bouts may contribute more to plant reproduction for the same number of flowers visited. Consequently, the magnitude of the differences in number of interactions of different insect types may be overridden by the magnitude of the differences in effectiveness as pollinators, even if the same pollinators consistently interact more frequently. We discuss two predictions regarding the validity of using interaction frequency as a surrogate for plant seed production (as a measure of total effect), depending on the degree of self-compatibility, plant size and floral display. We suggest that the role of interaction frequency must be tested for different species, environments, and across wider scales to validate its use as a surrogate for total effect in plant-pollinator networks. © 2011 Springer-Verlag.

Abad M.D.,University of Seville | Sanchez-Lopez J.C.,University of Seville
Wear | Year: 2013

A fully comprehensive study of the tribological behavior of palladium nanoparticles (Pd NPs) capped by tetrabutylammonium chains using a ball-on-disk tribometer under different conditions of applied load, concentration, tribometer motion, linear speed and nature of the counterface is revised. A low concentration of NPs (2. wt%) in tetrabutylammonium acetate was found sufficient to improve the tribological properties due to the formation of a protective transfer film (TF) comprised of metallic Pd. The increase of the applied load (up to 20. N, 1.82. GPa of contact pressure) confirmed the excellent extreme-pressure behavior avoiding the counterfaces from severe wear. After a running-in period whose duration depends on the operating conditions, the TF build-up allows to maintain a low contact electrical resistance through the contact (<0.1. kΩ) during the entire test. When the Pd NPs are used with ceramic counterfaces, the nanoparticles increase the load-bearing capabilities and performance of the base without forming TF, likely by mixed or boundary lubrication and healing effects. Finally, the Pd NPs are demonstrated to be useful as a thin solid lubricant film in reciprocating motion yielding a comparable tribological behavior. Hence, the presented surface Pd NPs can be very helpful to extend life of sliding components due to their high strength resistance providing a gateway to electrical conduction as well. © 2012 Elsevier B.V.

Luna Galiano Y.,University of Seville | Fernandez Pereira C.,University of Seville | Vale J.,University of Seville
Journal of Hazardous Materials | Year: 2011

The stabilization/solidification (S/S) of a municipal solid waste incineration (MSWI) fly ash containing hazardous metals such as Pb, Cd, Cr, Zn or Ba by means of geopolymerization technology is described in this paper. Different reagents such as sodium hydroxide, potassium hydroxide, sodium silicate, potassium silicate, kaolin, metakaolin and ground blast furnace slag have been used. Mixtures of MSWI waste with these kinds of geopolymeric materials and class F coal fly ash used as silica and alumina source have been processed to study the potential of geopolymers as waste immobilizing agents. To this end, the effects of curing conditions and composition have been tested. S/S solids are submitted to compressive strength and leaching tests to assess the results obtained and to evaluate the efficiency of the treatment. Compressive strength values in the range 1-9. MPa were easily obtained at 7 and 28 days. Concentrations of the metals leached from S/S products were strongly pH dependent, showing that the leachate pH was the most important variable for the immobilization of metals. Comparison of fly ash-based geopolymer systems with classical Portland cement stabilization methods has also been accomplished. © 2010 Elsevier B.V.

De La Rosa J.M.,University of Seville
IEEE Transactions on Circuits and Systems I: Regular Papers | Year: 2011

This paper presents a tutorial overview of ΣΔ modulators, their operating principles and architectures, circuit errors and models, design methods, and practical issues. A review of the state of the art on nanometer CMOS implementations is described, giving a survey of cutting-edge ΣΔ architectures, with emphasis on their application to the next generation of wireless telecom systems. © 2010 IEEE.

Kazmierkowski M.P.,Polish Academy of Sciences | Franquelo L.G.,University of Seville | Rodriguez J.,Federico Santa María Technical University | Perez M.A.,Federico Santa María Technical University | Leon J.I.,University of Sevilles
IEEE Industrial Electronics Magazine | Year: 2011

This article reviews the present state and trends in the development of key parts of controlled induction motor drive systems: converter topologies, modulation methods, as well as control and estimation techniques. Two- and multilevel voltage-source converters, current-source converters, and direct converters are described. The main part of all the produced electric energy is used to feed electric motors, and the conversion of electrical power into mechanical power involves motors ranges from less than 1 W up to several dozen megawatts. © 2011 IEEE.

Giner-Lamia J.,University of Seville | Lopez-Maury L.,University of Seville | Reyes J.C.,Centro Andaluz Of Biologia Molecular | Florencio F.J.,University of Seville
Plant Physiology | Year: 2012

Photosynthetic organisms need copper for cytochrome oxidase and for plastocyanin in the fundamental processes of respiration and photosynthesis. However, excess of free copper is detrimental inside the cells and therefore organisms have developed homeostatic mechanisms to tightly regulate its acquisition, sequestration, and efflux. Herein we show that the CopRS two-component system (also known as Hik31-Rre34) is essential for copper resistance in Synechocystis sp. PCC 6803. It regulates expression of a putative heavy-metal efflux-resistance nodulation and division type copper efflux system (encoded by copBAC) as well as its own expression (in the copMRS operon) in response to the presence of copper in the media. Mutants in this two-component system or the efflux system render cells more sensitive to the presence of copper in the media and accumulate more intracellular copper than the wild type. Furthermore, CopS periplasmic domain is able to bind copper, suggesting that CopS could be able to detect copper directly. Both operons (copMRS and copBAC) are also induced by the photosynthetic inhibitor 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone but this induction requires the presence of copper in the media. The reduced response of two mutant strains to copper, one lacking plastocyanin and a second one impaired in copper transport to the thylakoid, due to the absence of the PI-type ATPases PacS and CtaA, suggests that CopS can detect intracellular copper. In addition, a tagged version of CopS with a triple HA epitope localizes to both the plasma and the thylakoid membranes, suggesting that CopS could be involved in copper detection in both the periplasm and the thylakoid lumen. © 2012 American Society of Plant Biologists. All Rights Reserved.

Dominguez F.,University of Seville | Moreno J.,University of Seville | Cejudo F.J.,University of Seville
Journal of Experimental Botany | Year: 2012

Programmed cell death (PCD) is a crucial phenomenon in the life cycle of cereal grains. In germinating grains, the scutellum allows the transport of nutrients from the starchy endosperm to the growing embryo, and therefore it may be the last grain tissue to undergo PCD. Thus, the aim of this work was to analyse whether the scutellum of wheat grains undergoes PCD and to perform a morphological and biochemical analysis of this process. Scutellum cells of grains following germination showed a progressive increase of DNA fragmentation, and the TUNEL assay showed that PCD extended in an apical-to-basal gradient along the scutellum affecting epidermal and parenchymal cells. Electron-transmission microscopy revealed high cytoplasm vacuolation, altered mitochondria, and the presence of double-membrane structures, which might constitute symptoms of vacuolar cell death, whereas the nucleus appeared lobed and had an increased heterochromatin content as the most distinctive features. An acid-and Zn2+-dependent nucleolytic activity was identified in nuclear extracts of scutellum cells undergoing PCD. This nuclease was not detected in grains imbibed in the presence of abscisic acid, which inhibited germination. This nucleolytic activity promoted DNA fragmentation in vitro on nuclei isolated from healthy cells, thus suggesting a main role in nucleus dismantling during PCD. © 2012 The Author.

Hernandez W.Y.,University of Seville | Romero-Sarria F.,University of Seville | Centeno M.A.,University of Seville | Odriozola J.A.,University of Seville
Journal of Physical Chemistry C | Year: 2010

Gold-supported ceria and europium-doped ceria catalysts were prepared by the deposition-precipitation method. The influence of the pretreatment atmosphere and temperature on the concentration of oxygen vacancies and gold dispersion on the Au/CeEu(10) catalyst under actual reaction conditions was investigated by "in situ" X-ray diffraction and Raman analysis. By Raman spectroscopy, a preferential interaction of the gold with the support across the oxygen vacancies was established and correlated with the gold dispersion. The increase in the concentration of oxygen vacancies in the presence of hydrogen induces changes in the gold crystallite size by breaking-off and migration of gold nanoparticles toward the oxygen vacancies on the CeEu(10) support. The activity of the Au/CeEu(10) solid in the CO oxidation reaction was significantly improved when the catalyst was preactivated in a reducing atmosphere. This trend could be associated with the redispersion of gold together with the increase in the concentration of oxygen vacancies in the support. © 2010 American Chemical Society.

Malrieu J.P.,CNRS Laboratory for Quantum Chemistry and Physics | Caballol R.,Rovira i Virgili University | Calzado C.J.,University of Seville | De Graaf C.,Rovira i Virgili University | And 2 more authors.
Chemical Reviews | Year: 2014

The use of accurate model Hamiltonians is crucial to extract information on the magnetic interactions from the raw data obtained from magnetic susceptibility measurements, EPR, or NMR spectroscopy. Combining information from different experimental techniques can be used to propose topologies and magnitudes of the magnetic couplings in the system. It provides a rigorous and rational way to study the magnetic interactions in molecular complexes and extended systems without the need of fitting a set of parameters of an a priori defined model Hamiltonian. Theoretical treatments, able to discriminate between different physical effects, permit one to understand the various mechanisms involved in the magnetic couplings and to establish magneto-structural correlations. It has enabled theoreticians to discriminate between through space and through ligand interactions and to establish the balance between direct exchange, kinetic exchange, and spin polarization contributions to the magnetic coupling.

Ros A.,Institute Investigaciones Quimicas Csic Us | Fernandez R.,University of Seville | Lassaletta J.M.,Institute Investigaciones Quimicas Csic Us
Chemical Society Reviews | Year: 2014

The direct borylation of hydrocarbons via C-H activation has reached an impressive level of sophistication and efficiency, emerging as a fundamental tool in synthesis because of the versatility offered by organoboron compounds. As a remarkable particularity, the catalytic systems originally developed for these reactions are relatively insensitive to directing effects, and the regioselectivity of the borylations is typically governed by steric factors. Likely stimulated by the great synthetic potential of the expected functionalised organoboranes, however, many groups have recently focused on the development of complementary strategies for directed, site-selective borylation reactions where a directing group controls the course of the reaction. In this tutorial review, the different strategies and findings related to the development of these directed borylation reactions via C(sp2)-H or C(sp3)-H activation will be summarized and discussed. © 2014 the Partner Organisations.

Galera S.,University of Seville | Gutierrez Ortiz F.J.,University of Seville
Fuel | Year: 2015

Hydrogen and power production from supercritical water reforming of glycerol was techno-economically assessed, considering future states of technology because there is no demonstration plant using this technology. Two different configurations were proposed: supercritical water reforming (SCWR) and autothermal supercritical water reforming (ASCWR). A plant size of 1000 kg/h of glycerol was considered on a process flow-sheet simulated by Aspen Plus with the criterion of being energy self-sufficient. The results reveal that, although ASCWR presents better performance than SCWR in terms of energy efficiency, the investment capital and operational difficulties of ASCWR process leads to higher hydrogen production costs. The levelized production cost of hydrogen was evaluated using a discounted cash flow analysis with a discount rate of 10% and 100% equity financing. Thus, the minimum hydrogen selling price (achieved when net present value is zero) is 5.36 $/kg for SCWR and 5.75 $/kg for ASCWR. These values are somewhat higher than in a few conventional technologies, such as steam methane reforming, although lower than other renewable processes, such as wood gasification. In a future scenario, possible improvements in SCW reforming performance may lead to a decrease in the estimation of renewable hydrogen price. © 2014 Elsevier Ltd. All rights reserved.

Valverde J.M.,University of Seville | Sanchez-Jimenez P.E.,University of Seville | Perez-Maqueda L.A.,University of Seville
Journal of Physical Chemistry C | Year: 2015

In this work, we analyze limestone calcination kinetics at environmental conditions involving a CO2 partial pressure P close to the equilibrium pressure Peq by means of in situ X-ray diffraction (XRD) and thermogravimetric (TG) analyses. In contrast with previous empirical observations carried out mostly at conditions far from equilibrium (P/Peq « 1), our results show that the decarbonation rate decreases as the temperature in increased while P/Peq is kept constant, which is explained from a reaction mechanism including desorption of CO2 and the exothermic structural transformation from metastable CaO∗ nanocrystals to the stable CaO form. The crystal structure and sintering of nascent CaO during calcination has been investigated from in situ XRD analysis, physisorption analysis, and scanning electron microscopy (SEM), which shows that the ratio of the size of polycrystalline CaO grains to crystallite size increases linearly with the CO2 partial pressure in the calcination atmosphere. For high CO2 partial pressures, the size of CaO grains reaches a maximum value of around 1 μm, which leads to a residual surface area of about 1 m2/g, whereas in the limit P → 0 grain size and crystallite size (of the order of 10 nm) would coincide. Accordingly, sintering in the presence of CO2 would be triggered by the agglomeration of CaO crystals enhanced by CO2 adsorption, which increases the surface energy. The carbonation reactivity of CaO resulting from calcination scales proportionally to its surface area and is not determined by a growth of the CaO exposed surface along a preferred crystallographic direction wherein carbonation would be unfavorable as suggested in recent works. (Graph Presented). © 2015 American Chemical Society.

Hernandez S.B.,University of Seville | Cota I.,University of Seville | Ducret A.,Aix - Marseille University | Aussel L.,Aix - Marseille University | Casadesus J.,University of Seville
PLoS Genetics | Year: 2012

Bile possesses antibacterial activity because bile salts disrupt membranes, denature proteins, and damage DNA. This study describes mechanisms employed by the bacterium Salmonella enterica to survive bile. Sublethal concentrations of the bile salt sodium deoxycholate (DOC) adapt Salmonella to survive lethal concentrations of bile. Adaptation seems to be associated to multiple changes in gene expression, which include upregulation of the RpoS-dependent general stress response and other stress responses. The crucial role of the general stress response in adaptation to bile is supported by the observation that RpoS - mutants are bile-sensitive. While adaptation to bile involves a response by the bacterial population, individual cells can become bile-resistant without adaptation: plating of a non-adapted S. enterica culture on medium containing a lethal concentration of bile yields bile-resistant colonies at frequencies between 10 -6 and 10 -7 per cell and generation. Fluctuation analysis indicates that such colonies derive from bile-resistant cells present in the previous culture. A fraction of such isolates are stable, indicating that bile resistance can be acquired by mutation. Full genome sequencing of bile-resistant mutants shows that alteration of the lipopolysaccharide transport machinery is a frequent cause of mutational bile resistance. However, selection on lethal concentrations of bile also provides bile-resistant isolates that are not mutants. We propose that such isolates derive from rare cells whose physiological state permitted survival upon encountering bile. This view is supported by single cell analysis of gene expression using a microscope fluidic system: batch cultures of Salmonella contain cells that activate stress response genes in the absence of DOC. This phenomenon underscores the existence of phenotypic heterogeneity in clonal populations of bacteria and may illustrate the adaptive value of gene expression fluctuations. © 2012 Hernández et al.

Cabello A.,University of Seville | Cunha M.T.,Federal University of Minas Gerais
Physical Review Letters | Year: 2011

It has been argued that any test of quantum contextuality is nullified by the fact that perfect orthogonality and perfect compatibility cannot be achieved in finite precision experiments. We introduce experimentally testable two-qutrit violations of inequalities for noncontextual theories in which compatibility is guaranteed by the fact that measurements are performed on separated qutrits. The inequalities are inspired by the basic building block of the Kochen-Specker proof of quantum contextuality for a qutrit, despite the fact that their proof is completely independent of it. © 2011 American Physical Society.

Alvarez-Galvez J.,University of Seville | Salvador-Carulla L.,University of Sydney
PLoS ONE | Year: 2013

Introduction:Studies have shown that perceived discrimination has an impact on our physical and mental health. A relevant part of literature has highlighted the influence of discrimination based on race or ethnicity on mental and physical health outcomes. However, the influence of other types of discrimination on health has been understudied. This study is aimed to explore how different types of discrimination are related to our subjective state of health, and so to compare the intensity of these relationships in the European context.Methods:We have performed a multilevel ordered analysis on the fifth wave of the European Social Survey (ESS 2010). This dataset has 52,458 units at individual level that are grouped in 26 European countries. In this study, the dependent variable is self-rated health (SRH) that is analyzed in relationship to ten explanatory variables of perceived discrimination: color or race, nationality, religion, language, ethnic group, age, gender, sexuality, disability and others.Results:The model identifies statistically significant differences in the effect that diverse types of perceived discrimination can generate on the self-rated health of Europeans. Specifically, this study identifies three well-defined types of perceived discrimination that can be related to poor health outcomes: (1) age discrimination; (2) disability discrimination; and (3) sexuality discrimination. In this sense, the effect on self-rated health of perceived discrimination related to aging and disabilities seems to be more relevant than other types of discrimination in the European context with a longer tradition in literature (e.g. ethnic and/or race-based).Conclusion:The present study shows that the relationship between perceived discrimination and health inequities in Europe are not random, but systematically distributed depending on factors such as age, sexuality and disabilities. Therefore the future orientation of EU social policies should aim to reduce the impact of these social determinants on health equity. © 2013 Alvarez-Galvez et al.

Hohl M.,Sloan Kettering Cancer Center | Kochanczyk T.,Wrocław University | Tous C.,University of Seville | Aguilera A.,University of Seville | And 2 more authors.
Molecular Cell | Year: 2015

Rad50 contains a conserved Zn2+ coordination domain (the Rad50 hook) that functions as a homodimerization interface. Hook ablation phenocopies Rad50 deficiency in all respects. Here, we focused on rad50 mutations flanking the Zn2+-coordinating hook cysteines. These mutants impaired hook-mediated dimerization, but recombination between sister chromatids was largely unaffected. This may reflect that cohesin-mediated sister chromatid interactions are sufficient for double-strand break repair. However, Mre11 complex functions specified by the globular domain, including Tel1 (ATM) activation, nonhomologous end joining, and DNA double-strand break end resection were affected, suggesting that dimerization exerts a broad influence on Mre11 complex function. These phenotypes were suppressed by mutations within the coiled-coil and globular ATPase domains, suggesting a model in which conformational changes in the hook and globular domains are transmitted via the extended coils of Rad50. We propose that transmission of spatial information in this manner underlies the regulation of Mre11 complex functions. © 2015 Elsevier Inc.

Brey J.J.,University of Seville | Khalil N.,University of Seville
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2010

Two granular gases separated by an adiabatic piston and initially in the same macroscopic state are considered. It is found that a phase transition with an spontaneous symmetry breaking occurs. When the mass of the piston is increased beyond a critical value, the piston moves to a stationary position different from the middle of the system. The transition is accurately described by a simple kinetic model that takes into account the velocity fluctuations of the piston. Interestingly, the final state is not characterized by the equality of the temperatures of the subsystems but by the cooling rates being the same. Some relevant consequences of this feature are discussed. © 2010 The American Physical Society.

Talavera M.,University of Seville | Arista M.,University of Seville | Ortiz P.L.,University of Seville
Journal of Ecology | Year: 2012

1. Seed dispersal is crucial in determining the spatial patterns of plant populations, and selection pressure for dispersal varies over different scales. However, few empirical studies have assessed differences in dispersal traits in a biogeographical context. 2. We studied dispersal traits in 46 populations of Rumex bucephalophorus from mainland and island locations, and from different habitats to test predictions of how insularity and habitat characteristics affect both dispersability (dispersal capacity and number of dispersible diaspores) and dispersal-distance strategy. We also conducted a greenhouse experiment to compare dispersability of plants in nature and a controlled environment. 3. Dispersability drastically changed when plants were cultivated in the greenhouse, revealing a high phenotypic plasticity for dispersal and showing that the maternal environment directly influences dispersal. However, dispersal-distance strategy, estimated by the production of either long diaspores (LD) or short diaspores (SD), seems to be genetically determined. Dispersability was markedly affected by the habitat in which the plants develop, but the patterns found are not consistent with theoretical predictions. We found two contrasting patterns of dispersal on islands: Atlantic island populations showed a trend to seed monomorphism and mid-dispersal strategy, whilst Mediterranean island populations showed seed heteromorphism and long-dispersal strategy. These contrasting patterns support theoretical predictions that long-distance dispersal evolves in heteromorphic plants, whilst in monomorphic plants only local dispersal evolves. Lastly, we have found a clear mid-dispersal-distance strategy in coastal sands and Atlantic islands; we suggest that the low environmental variation shared by these two zones selects for shorter distances of dispersal. 4. Synthesis. Most models describing the evolution of dispersal strategies assume that forces selecting for decreased dispersability also select for decreased dispersal distances. However, in R. bucephalophorus dispersal distance and dispersability showed contrasting patterns of variation. The fact that these two traits are differently determined could suggest that they can respond in a different manner to selective pressures. Most models describing the evolution of dispersal strategies assume that forces selecting for decreased dispersability also select for decreased dispersal distances. However, in Rumex bucephalophorus dispersal distance and dispersability showed contrasting patterns of variation. The fact that these two traits are differently determined could suggest that they can respond in a different manner to selective pressures. © 2012 British Ecological Society.

Rubio-Escudero C.,University of Seville
AI Communications | Year: 2012

We propose a novel methodology to extract gene expression profiles from microarray experiments based on the application of an AI process (multiobjective optimization) to establish relationships between each profile and the most suitable existing technique to discover it. We first determine a space of potential hypothesis (techniques) aggregating well-known and widely used methods. Then, for each profile, we perform a multiobjective search over the space of hypothesis in order to find the technique (or aggregation of them) that better finds it. © 2012 - IOS Press and the authors. All rights reserved.

Lopez-Igual R.,University of Seville | Flores E.,University of Seville | Herrero A.,University of Seville
Journal of Bacteriology | Year: 2010

Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that carries out N2 fixation in specialized cells called heterocysts, which exchange nutrients and regulators with the filament's vegetative cells that perform the photosynthetic fixation of CO2. The Anabaena genome carries two genes coding for alkaline/neutral invertases, invA and invB. As shown by Northern analysis, both genes were expressed monocistronically and induced under nitrogen deprivation, although induction was stronger for invB than for invA. Whereas expression of an InvA-N-GFP fusion (green fluorescent protein [GFP] fused to the N terminus of the InvA protein [InvA-N]) was homogeneous along the cyanobacterial filament, consistent with the lack of dependence on HetR, expression of an InvB-N-GFP fusion upon combined nitrogen deprivation took place mainly in differentiating and mature heterocysts. In an hetR genetic background, the InvB-N-GFP fusion was strongly expressed all along the filament. An insertional mutant of invA could grow diazotrophically but was impaired in nifHDK induction and exhibited an increased frequency of heterocysts, suggesting a regulatory role of the invertase-mediated carbon flux in vegetative cells. In contrast, an invB mutant was strongly impaired in diazotrophic growth, showing a crucial role of sucrose catabolism mediated by the InvB invertase in the heterocysts. Copyright © 2010, American Society for Microbiology. All Rights Reserved.

Garcia-Sanchez P.,University of Twente | Ramos A.,University of Seville | Mugele F.,University of Twente
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2010

Mixing within sessile drops can be enhanced by generating internal flow patterns using ac electrowetting. While for low ac frequencies, the flow patterns have been attributed to oscillations of the drop surface, we provide here the driving mechanism of the hitherto unexplained high-frequency flows. We show that: (1) the electric field in the liquid bulk becomes important, leading to energy dissipation due to Joule heating and a temperature increase of several degrees Celsius, and (2) the fluid flow at these frequencies is generated by electrothermal effect, i.e., gradients in temperature give rise to gradients in conductivity and permittivity, the electric field acting on these inhomogeneities induces an electrical body force that generates the flow. We solved numerically the equations for the electric, temperature and flow fields. The temperature is obtained from a convection-diffusion equation where Joule heating is introduced as a source term. From the solution of the electric field and the temperature, we compute the electrical force that acts as a body force in Stokes equations. Our numerical results agree with previous experimental observations. © 2010 The American Physical Society.

Levai G.,Hungarian Academy of Sciences | Arias J.M.,University of Seville
Physical Review C - Nuclear Physics | Year: 2010

The spherical to deformed γ-unstable shape transition in nuclei is discussed in terms of the sextic oscillator as a γ-independent potential in the Bohr Hamiltonian. The wave functions, energy eigenvalues, and electric quadrupole and monopole transition rates are calculated in closed analytical form for the lowest-lying energy levels. It is shown that the locus of critical points for the spherical to deformed γ-unstable shape phase transition corresponds to a parabola in the parameter space of the model. The ratios of energy eigenvalues and electromagnetic transition probabilities are constant along this parabola. It is thus possible to associate parameter-free benchmark values to the ratios of relevant observables at the critical point of the transition that can be compared to experimental data. In addition, systematic studies of the shape evolution in isotope chains can be performed within the model. As an application, the model parameters are fitted to the energy spectra of the chains of even-even Ru, Pd, and Cd isotopes and the electric quadrupole transition probabilities are calculated. It is found that Ru104, Pd102, and Cd106,108 nuclei, which are usually considered to be good candidates for the E(5) symmetry, lie rather close to the critical parabola that separates the spherical and deformed γ-unstable domains. The isotope Cd116 is proposed as a new candidate for a similar critical-point nucleus. © 2010 The American Physical Society.

Quintero N.R.,University of Seville | Cuesta J.A.,Charles III University of Madrid | Alvarez-Nodarse R.,University of Seville
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2010

Equations describing the evolution of particles, solitons, or localized structures, driven by a zero-average, periodic, external force, and invariant under time reversal and a half-period time shift, exhibit a ratchet current when the driving force breaks these symmetries. The biharmonic force f (t) = ε1 cos (qωt+ Φ1) + ε2 cos (pωt+ Φ2) does it for almost any choice of Φ1 and Φ2, provided p and q are two coprime integers such that p+q is odd. It has been widely observed, in experiments in semiconductors, in Josephson junctions, photonic crystals, etc., as well as in simulations, that the ratchet current induced by this force has the shape v Ε1p Ε2q cos (p Φ1 -q Φ2 + θ0) for small amplitudes, where θ0 depends on the damping (θ0 =π/2 if there is no damping, and θ0 =0 for overdamped systems). We rigorously prove that this precise shape can be obtained solely from the broken symmetries of the system and is independent of the details of the equation describing the system. © 2010 The American Physical Society.

Avrigeanu M.,Horia Hulubei National Institute of Physics and Nuclear Engineering | Moro A.M.,University of Seville
Physical Review C - Nuclear Physics | Year: 2010

Experimental elastic-scattering angular distributions for deuteron interaction with Cu63 and Nb93 targets are compared with calculations performed within the continuum-discretized coupled-channels (CDCC) method, in which coupling to breakup channels is explicitly taken into account. The calculated elastic breakup cross sections are compared with the predictions of an empirical parametrization for a wide range of deuteron incident energies. The good agreement between the calculations and the systematics at the energies where data are available indicates that the CDCC method permits a useful assessment of empirical parametrizations and provides useful guidance for the extrapolation of these parametrizations beyond the energies formerly considered. © 2010 The American Physical Society.

Sanchez-de-la-Torre M.,Hospital Universitari Arnau Of Vilanova Santa Maria | Sanchez-de-la-Torre M.,Research Center Biomedica En Red Of Enfermedades Respiratorias Ciberes | Campos-Rodriguez F.,University of Seville | Barbe F.,Hospital Universitari Arnau Of Vilanova Santa Maria | Barbe F.,Research Center Biomedica En Red Of Enfermedades Respiratorias Ciberes
The Lancet Respiratory Medicine | Year: 2013

Obstructive sleep apnoea (OSA) is a common health concern caused by repeated episodes of collapse of the upper airway during sleep. The events associated with OSA lead to brain arousal, intrathoracic pressure changes, and intermittent episodes of hypoxaemia and reoxygenation. These events activate pathways such as oxidative stress, sympathetic activation, inflammation, hypercoagulability, endothelial dysfunction, and metabolic dysregulation that predispose patients with OSA to hypertension and atherosclerosis. OSA is a common cause of systemic hypertension and should be suspected in hypertensive individuals, especially those with resistant hypertension. In patients with OSA, continuous positive airway pressure (CPAP) treatment reduces blood pressure, and its effects are related to compliance and baseline blood pressure. Evidence suggests that OSA is a risk factor for stroke and heart failure. An association between coronary heart disease and OSA seems to be limited to middle-aged men (30-70 years). Cardiac rhythm disorders occur in about half of patients with OSA, but their clinical relevance is still unknown. The association of OSA with cardiovascular risk is mainly based on studies in men, and an association has yet to be established in women. Data on older patients is similarly scarce. Currently, there is not enough evidence to support treatment with CPAP for primary or secondary prevention of cardiovascular disease. © 2013 Elsevier Ltd.

Tejada M.,University of Seville | Masciandaro G.,National Research Council Italy
Ecotoxicology and Environmental Safety | Year: 2011

In this paper we studied the bioremediation effects of a soil artificially contaminated by benzo(a)pyrene with and without two organic wastes (organic municipal solid waste, MSW, and poultry manure, PM) and with and without worms (Eisenia fetida) over 90 days. For the organic treatments, soil samples were mixed with MSW at a rate of 10% or PM at a rate of 7.6%, in order to apply the same amount of organic matter to the soil. An unamended and non-polluted soil was used as control. Cellulase and glutathione-S-transferase activities in worms and the earthworms' weight were measured at four different incubation times (3, 15, 60 and 90 days). Cocoon numbers, average weight per cocoon and number of juveniles per cocoon were measured 30 days after the benzo(a)pyrene exposure. Extractable benzo(a)pyrene in soils and E. fetida was determined during the incubation period. To observe the effects of bioremediation of the contaminated soil, ATP, urease and phosphatase activities were measured. At the end of the incubation period and when compared with the polluted soil without worms and organic matter, the extractable benzo(a)pyrene decreased by 41.2% for the unamended polluted soil and without worms, by 45.8% for the organic-PM polluted soil and without worms, 48.3% for the organic-MSW polluted soil and without worms, 55.4% for the organic-PM polluted soil and with worms, and 66.3% for the organic-MSW polluted soil and with worms. This meant that worm hydrocarbon absorption was lowest in the contaminated soil amended with MSW and with worms, causing an increase in catabolic activity of the soil. These results suggested that the co-application of organic wastes and E. fetida for the bioremediation of benzo(a)pyrene polluted soil is potentially advantageous. © 2010 Elsevier Inc.

Troca-Marin J.A.,University of Seville | Alves-Sampaio A.,University of Seville | Alves-Sampaio A.,University Miguel Hernández | Montesinos M.L.,University of Seville
Progress in Neurobiology | Year: 2012

Local translation of dendritic mRNAs is a key aspect of dendrite and spine morphogenesis and synaptic plasticity, two phenomena generally compromised in intellectual disability disorders. Mammalian target of rapamycin (mTOR) is a protein kinase involved in a plethora of functions including dendritogenesis, plasticity and the regulation of local translation. Hence, this kinase may well be implicated in intellectual disability. Hyperactivation of mTOR has been recently reported in mouse models of Fragile X and tuberous sclerosis, two important causes of intellectual disability. Moreover, local dendritic translation seems to be increased in Fragile X syndrome. Recent findings show that the mTOR pathway is also deregulated in murine models of Rett's syndrome and Down's syndrome. As in Fragile X, local dendritic translation seems to be abnormally active in Down's syndrome mice, while rapamycin, a Food and Drug Administration-approved mTOR inhibitor, restores normal rates of translation. Rapamycin administration in tuberous sclerosis mice rescues deficits in behavior and synaptic plasticity. Indeed, mTOR-dependent deregulation of local translation may be a common trait in different intellectual deficiencies, suggesting that mTOR inhibitors may have significant therapeutic potential for the treatment of diverse forms of cognitive impairment. © 2012 Elsevier Ltd.

Arenas-Gaitan J.,University of Seville | Ramirez-Correa P.E.,Católica del Norte University | Javier Rondan-Cataluna F.,University of Seville
Computers and Education | Year: 2011

The main objective of this paper is to examine cultural differences and technology acceptances from students of two universities, one is from a European country: Spain, and the other is in Latin America: Chile. Both of them provide their students with e-learning platforms. The technology acceptance model (TAM) and Hofstede's cultural dimensions are the tools used to measure the acceptance and use of web-based learning platforms and cultural diversity of respondents, respectively. In summary, we can affirm that the sample of tertiary Spanish and Chilean students are culturally different with regard to some of Hofstede's dimensions, but their behavior of acceptance of e-learning technology globally matches according to the TAM model. This study provides relevant implications for on-line courses managers' who have tertiary students from different nationalities. © 2010 Elsevier Ltd. All rights reserved.

Fernandez J.M.G.,University of Seville
Topics in Current Chemistry | Year: 2010

This review provides an overview of the current status of the chemistry and biology of di-d-fructose dianhydrides (DFAs) with a focus on their potential as functional foods. The history of this family of cyclic ketodisaccharides has expanded for almost 100 years and offers a paradigmatic example of artificial synthetic molecules that were identified as natural products later on and finally encountered in our own table. Issued from fundamental investigations on the reactivity of carbohydrates in strongly acidic media, DFAs remained laboratory curiosities for decades. Early reports on their isolation from plants raised doubts, until the formation of some DFA representatives by the action of microorganisms on fructans was reported in the middle 1980s. Since then, research on DFAs has run in parallel in the areas of microbiology and carbohydrate chemistry. Evidence of the potential of these compounds as functional food was accumulated from both sides, with the development of biotechnological processes for mass production of selected candidates and of chemical methodologies to prepare DFA-enriched products from sucrose or inulin. In 1994 a decisive discovery in the field took place in the laboratory of Jacques Defaye in Grenoble, France: the presence of DFAs in a commercial sucrose caramel was evidenced in a quite significant 18% mass proportion! The development of an efficient analytical protocol for DFAs and the stereoselective synthesis of individual standards allowed one to demonstrate that DFAs and their glycosylated derivatives (glycosyl-DFAs) are universally formed during caramelization reactions. They are not potential food products; they have actually always been in our daily food. Most important, they seem to exert beneficial effects: they are acariogenic, low-caloric, and promote the growth of beneficial microflora in the gut. Most recent evidence indicates that DFAs can even protect the intestinal tract against agressive agents favor the assimilation of antioxidants, and act as a drug-like food for the treatment of colon ailments such as inflammatory bowel disease (Crohn disease). The development of efficient methodologies for the preparation of DFA-enriched caramels, compatible with the food and agricultural industry regulations, may lead to new natural functional foods and nutraceuticals based on DFAs in the near future. © 2010 Springer-Verlag Berlin Heidelberg.

Meucci A.,University of Pavia | Barbaro M.B.,University of Turin | Caballero J.A.,University of Seville | Giusti C.,University of Pavia | Udias J.M.,Complutense University of Madrid
Physical Review Letters | Year: 2011

The results of two relativistic models with different descriptions of the final-state interactions are compared with the MiniBooNE data of charged-current quasielastic cross sections. The relativistic mean field model uses the same potential for the bound and ejected nucleon wave functions. In the relativistic Green's function model, the final-state interactions are described in the inclusive scattering consistently with the exclusive scattering using the same complex optical potential. The relativistic Green's function results describe the experimental data for total cross sections without the need to modify the nucleon axial mass. © 2011 American Physical Society.

Potel G.,University of Seville | Barranco F.,University of Seville | Marini F.,University of Milan | Idini A.,University of Milan | And 2 more authors.
Physical Review Letters | Year: 2011

Absolute values of two-particle transfer cross sections along the Sn-isotopic chain are calculated. They agree with measurements within errors and without free parameters. Within this scenario, the predictions concerning the absolute value of the two-particle transfer cross sections associated with the excitation of the pairing vibrational spectrum expected around the recently discovered closed shell nucleus Sn8250132 and the very exotic nucleus Sn5050100 can be considered quantitative, opening new perspectives in the study of pairing in nuclei. © 2011 American Physical Society.

Prados A.,University of Seville | Lasanta A.,University of Seville | Hurtado P.I.,University of Granada
Physical Review Letters | Year: 2011

We analyze the fluctuations of the dissipated energy in a simple and general model where dissipation, diffusion, and driving are the key ingredients. The full dissipation distribution, which follows from hydrodynamic fluctuation theory, shows non-Gaussian tails and no negative branch, thus violating the fluctuation theorem as expected from the irreversibility of the dynamics. It exhibits simple scaling forms in the weak- and strong-dissipation limits, with large fluctuations favored in the former case but strongly suppressed in the latter. The typical path associated with a given dissipation fluctuation is also analyzed in detail. Our results, confirmed in extensive simulations, strongly support the validity of hydrodynamic fluctuation theory to describe fluctuating behavior in driven dissipative media. © 2011 American Physical Society.

Gomez F.,University of Santiago de Compostela | Iglesias A.,University of Santiago de Compostela | Doblado F.S.,University of Seville
Physics in Medicine and Biology | Year: 2010

This work focuses on neutron monitoring at clinical linac facilities during high-energy modality radiotherapy treatments. Active in-room measurement of neutron fluence is a complex problem due to the pulsed nature of the fluence and the presence of high photon background, and only passive methods have been considered reliable until now. In this paper we present a new active method to perform real-time measurement of neutron production around a medical linac. The device readout is being investigated as an estimate of patient neutron dose exposure on each radiotherapy session. The new instrument was developed based on neutron interaction effects in microelectronic memory devices, in particular using neutron-sensitive SRAM devices. This paper is devoted to the description of the instrument and measurement techniques, presenting the results obtained together with their comparison and discussion. Measurements were performed in several standard clinical linac facilities, showing high reliability, being insensitive to the photon fluence and EM pulse present inside the radiotherapy room, and having detector readout statistical relative uncertainties of about 2% on measurement of neutron fluence produced by 1000 monitor units irradiation runs. © 2010 Institute of Physics and Engineering in Medicine.

Campos J.,University of Seville | Peloso R.,University of Seville | Carmona E.,University of Seville
Angewandte Chemie - International Edition | Year: 2012

Often proposed, hard to catch: The bis(platinacycle) trans-[Pt{P[2,6- (CH2)(Me)C6H3]iPr2}2] experiences α-hydride abstraction by action of Ph3C +PF6 - to yield a trans-alkyl-alkylidene species. The electrophilicity of its {Pt=CH}+ unit is demonstrated by ylide formation by reaction with Lewis bases, stepwise hydrogenation, and carbene cross-coupling with N2C(H)CO2Et (see scheme). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

De La Rosa J.M.,University of Seville
ISCAS 2012 - 2012 IEEE International Symposium on Circuits and Systems | Year: 2012

This paper discusses the use of behavioral simulation techniques to improve the quality of teaching/learning circuits and systems for communications. The proposed pedagogical methodology has been applied in several electrical engineering courses, in both undergraduate and master degrees. The method allows students to better understand some complex circuit-and physical-level phenomena, by describing them at a higher abstraction level. In addition to enhance their understanding of design problems and skills, students become more motivated and satisfied. As an application, two case studies are considered in this work: a radio-frequency front-end system and an analog-to-digital converter. In both cases, behavioral models of the different building blocks have been implemented in MATLAB/SIMULINK and used by the students enrolled in two courses named: Electronic Circuits for Communications and Wireless Transceivers: Standards, Techniques and Architectures. © 2012 IEEE.

Gomez-Quiles C.,University of Seville | Gomez-Exposito A.,University of Seville | De La Villa Jaen A.,University of Seville
IEEE Transactions on Smart Grid | Year: 2012

In the upcoming smart grid environment many more measurements will be available, which can be locally processed by the so-called substation state estimator (SSE). Distribution substations serve energy to a large set of feeders, each one delivering power to a certain number of secondary transformers. In this context, the SSE may have to deal with a huge network model, comprising several hundred or even thousand buses. Taking advantage of the weak electrical coupling existing among the set of feeders connected to the same or adjacent substations, a two-stage procedure is proposed in this paper to efficiently solve the SSE. In the first stage the overall SE is decomposed into f+s WLS subproblems (f and s being the total number of feeders and substations, respectively), which are then solved in a decoupled manner. The second stage, involving a linear WLS problem, consists of coordinating the solution provided by each subsystem (feeder or substation). The proposed solution scheme has a number of advantages, as shown by the case studies. © 2012 IEEE.

Reina-Romo E.,University of Seville | Sanz-Herrera J.A.,University of Seville
Computer Methods in Applied Mechanics and Engineering | Year: 2011

Many aerospace, aircraft or automotive mechanical components are joined together by using a structural adhesive. Adherend-to-adherend joint performance is usually carried out by a thin adhesive layer such that loads are transferred through this region, being then a critical point in the design. In order to ensure a proper behaviour of the adhesive under dynamical, mechanical, thermal or rheological loads, they are typically reinforced with a second phase stiffer material in addition to the adhesive matrix. Due to the intrinsic nature of the matrix, it may be approached using an elastic-plastic behaviour. Under these circumstances the adhesive inherently shows a heterogeneous microstructure whereas the loads are applied at the macroscopic adherend scale. In this work, a multiscale formulation is developed to analyze particle-reinforced adhesive joints. The adherend and the adhesive region, which is modelled using cohesive elements, stand macroscopically. On the other hand, the macroscopic adhesive behaviour is obtained by a direct analysis of the two-distinguished phases interaction at the microscopic level, using micromechanics and homogenization. The presented approach provides macroscopic as well as microscopic information about load distribution avoiding phenomenological lab fitting, case to case, of the overall macroscopic behaviour of the adhesive. © 2011 Elsevier B.V.

Garcia J.M.,University of Seville | Ruiz D.,University of Seville | Ruiz-Cortes A.,University of Seville
Journal of Web Semantics | Year: 2012

Semantic Web Services discovery is commonly a heavyweight task, which has scalability issues when the number of services or the ontology complexity increase, because most approaches are based on Description Logic reasoning. As a higher number of services becomes available, there is a need for solutions that improve discovery performance. Our proposal tackles this scalability problem by adding a preprocessing stage based on two SPARQL queries that filter service repositories, discarding service descriptions that do not refer to any functionality or non-functional aspect requested by the user before the actual discovery takes place. This approach fairly reduces the search space for discovery mechanisms, consequently improving the overall performance of this task. Furthermore, this particular solution does not provide yet another discovery mechanism, but it is easily applicable to any of the existing ones, as our prototype evaluation shows. Moreover, proposed queries are automatically generated from service requests, transparently to the user. In order to validate our proposal, this article showcases an application to the OWL-S ontology, in addition to a comprehensive performance analysis that we carried out in order to test and compare the results obtained from proposed filters and current discovery approaches, discussing the benefits of our proposal. © 2012 Elsevier B.V. All rights reserved.

Suarez de Vivero J.L.,University of Seville | Rodriguez Mateos J.C.,University of Seville
Marine Policy | Year: 2010

Owing to their style and economic impact, Brazil, Russia, India and China (the BRIC countries) are destined to become relevant actors in the new ocean governance. The following working hypothesis is sustained: the BRIC countries, due to the potential of their maritime territories, can be considered to be emerging maritime powers capable of displacing some of the historical maritime powers. This would also entail a shift of strategic maritime space towards the southern hemisphere. Other emerging maritime scenarios associated with the BRIC countries include the Russian Arctic, and the Indo-Pacific ocean belt, or "string of pearls", as it is known. Factors such as competitiveness, maritime leadership and ocean governance are thus placed in a new economic and political context where they might be redefined and adapted to the circumstances of the BRIC block and other emerging countries, the majority of which are subject to demographic pressure and a high degree of poverty. The most relevant conclusions point to the emergence of a new type of neo-navalism, on the one hand-a BRIC version of traditional sea power and, on the other, a possible threat to the EU's Integrated Maritime Policy under pressure from strong competitiveness in a highly internationalised environment, forcing changes in its original approach with its distinct social profiles and commitment to latest generation rights. © 2010 Elsevier Ltd.

Maynar P.,University of Seville | Trizac E.,University Paris - Sud
Physical Review Letters | Year: 2011

In its continuous version, the entropy functional measuring the information content of a given probability density may be plagued by a "measure" problem that results from improper weighting of phase space. This issue is addressed considering a generic collision process whereby a large number of particles or agents randomly and repeatedly interact in pairs, with prescribed conservation law(s). We find a sufficient condition under which the stationary single-particle distribution function maximizes an entropylike functional, that is free of the measure problem. This condition amounts to a factorization property of the Jacobian associated with the binary collision law, from which the proper weighting of phase space directly follows. © 2011 American Physical Society.

Gomez-Barea A.,University of Seville | Ollero P.,University of Seville | Leckner B.,Chalmers University of Technology
Fuel | Year: 2013

In fluidized-bed gasification (FBG) of biomass and waste the temperature is maintained relatively low to prevent agglomeration. This slows down carbon conversion in conventional FBG, and a gas with relatively high concentration of tar is generated. Then the gasification efficiency is reduced and utilization of the gas is difficult in applications where the gas is cooled or compressed. In the present work the conversion of char and tar is studied to identify the main factors hindering complete conversion of the fuel into a product gas that is free from tar. It is concluded that char conversion can be increased by solids recirculation in directly heated FBG (stand-alone units) or by burning the char in a separate chamber in indirectly heated FBG. However, the tar content of the gas remains high, making gas cleaning necessary. Downstream cleaning of gas by catalytic cracking and/or scrubbing is complex and/or expensive for small to medium gasification plants, so conversion of tar within the gasifier is preferred. The optimization of conventional directly heated FBG by use of in-bed catalyst and distribution of the gasification agent to various zones of the gasifier, although improving the process, is not sufficient to attain the gas purity required for cold gas applications. Staged gasification is a suitable way to reach high char conversion, while yielding a gas with low concentration of heavy tar. Most of the staged-gasification developments proposed up to date have been based on fixed-beds, thus having relatively small capacity. A recently proposed concept to achieve almost complete tar and char conversion in fluidized bed is presented. © 2012 Elsevier Ltd. All rights reserved.

Rivada-Wheelaghan O.,University of Seville | Ortuno M.A.,Autonomous University of Barcelona | Diez J.,University of Oviedo | Lledos A.,Autonomous University of Barcelona | Conejero S.,University of Seville
Angewandte Chemie - International Edition | Year: 2012

Small change matters: T-shaped Pt II complexes with less flexible substituents, than, for example, isopropyl or tert-butyl groups, on N-heterocyclic carbene (NHC) ligands allow for C-H bond activation reactions of aromatic compounds (see scheme; BAr f 4 -= tetrakis[(3,5-trifluoromethyl)phenyl]borate; F yellow, Pt red). NHC substituents that are not highly branched prevent agostic interactions and reduce the barriers to achieve the C-H bond cleavage. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vetter M.,Ludwig Maximilians University of Munich | Sousa A.,University of Seville
Fundamental and Applied Limnology | Year: 2012

In the past decades, nutrient concentrations in several pre-Alpine lakes in central Europe have increased due to human activity in the catchment area. Here, we examine whether this trend will continue in the future, through our analysis of the development of the trophic status, over a period of 25 years (1984 - 2009), of the pre-Alpine, dimictic tempered Lake Ammersee (South-Eastern Germany). The lake showed signs of an elevated eutrophic status until the 1990s. Immense management activities in the catchment area led to a reduction in the nutrient load in the tributaries. The study of dissolved oxygen, total phosphorus (TP) and chlorophyll-a revealed a substantial improvement in the trophic conditions of the lake. We identified a transition period in the development of trophic levels during the years 1996/1997. Therefore, our investigation is divided into two periods: 1984 -1996 and 1997- 2009. By comparing values during these two periods, we found that the annual mean TP concentrations of the complete water column declined from 18.2 μg l -1 (1984 -1996) to 8.8 μg l-1 (1997-2009). During this period the chlorophyll-a values are in relationship to other trophic variables such as TP, dissolved oxygen and sight depths (R2 between 0.41 and 0.56). At the same time, during the summer months, the surface temperature in the epilimnion increased (by about 0.8 K per decade), which was approximately in line with the thermal increase (about 0.6 K per decade) in the northern hemisphere (Pearson's correlation coefficient, omitting 2006, of 0.81). In conclusion, in the case of Lake Ammersee, a decrease in nutrient input has led, most recently (1997- 2009), to a substantial improvement in the trophic state. This improvement is fundamentally a result of measures taken to correct any anthropogenic impact. Nevertheless, we show that the thermal stability of the lake reacts to climate-triggered alterations. Therefore it seems that the impact of recent climate change on trophic conditions will have to be monitored closely in the future. © 2012 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.

Frias J.E.,University of Seville | Flores E.,University of Seville
Journal of Bacteriology | Year: 2010

In the filamentous, heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120, expression of the nitrate assimilation nirA operon takes place in the absence of ammonium and the presence of nitrate or nitrite. Several positive-action proteins that are required for expression of the nirA operon have been identified. Whereas NtcA and NtcB exert their action by direct binding to the nirA operon promoter, CnaT acts by an as yet unknown mechanism. In the genome of this cyanobacterium, open reading frame (ORF) all0605 (the nirB gene) is found between the nirA (encoding nitrite reductase) and ntcB genes. A nirB mutant was able to grow at the expense of nitrate as a nitrogen source and showed abnormally high levels of nirA operon mRNA both in the presence and in the absence of nitrate. This mutant showed increased nitrate reductase activity but decreased nitrite reductase activity, an imbalance that resulted in excretion of nitrite, which accumulated in the extracellular medium, when the nirB mutant was grown in the presence of nitrate. A nirA in-frame deletion mutant also showed a phenotype of increased expression of the nirA operon in the absence of ammonium, independent of the presence of nitrate in the medium. Both NirB and NirA are therefore needed to keep low levels of expression of the nirA operon in the absence of an inducer. Because NirB is also needed to attain high levels of nitrite reductase activity, NirA appears to be a negative element in the nitrate regulation of expression of the nirA operon in Anabaena sp. strain PCC 7120. Copyright © 2010, American Society for Microbiology. All Rights Reserved.

Santos-Gally R.,University of Seville | Vargas P.,Real Jardin Botanico | Arroyo J.,University of Seville
Journal of Biogeography | Year: 2012

Aim Our aims were: (1) to reconstruct the phylogenetic relationships of daffodils (Narcissus), focusing on the lowland subgenus Hermione and the mountain section Apodanthi; (2) to estimate the temporal setting of diversification; (3) to reconstruct the migration patterns of the lineages; and (4) to examine the microevolutionary differentiation of the wide-ranging Narcissus tazetta group across the Mediterranean. Location The Mediterranean Basin. Methods Plastid (trnT-L, trnL-F and ndhF) sequences were obtained from 63 populations representing 23 species of Narcissus and combined with published data from 16 species. Phylogenetic relationships and dating were inferred by Bayesian analysis based on geological events and divergence estimates of closely related taxa. A dispersal-extinction-cladogenesis analysis was performed using maximum likelihood methods to infer ancestral geographical distributions, and phylogeographical reconstruction was performed using coalescence analysis. Results Subgenus Hermione is not recognized as a monophyletic group because two of the nine species were found to have a close relationship with the subgenus Narcissus. The results on section Apodanthi confirmed previous findings of its monophyly and phylogenetic relationships within this mountain group. Molecular dating and ancestral range reconstructions suggest that the ancestor of Narcissus originated in the Iberian Peninsula during the Late Oligocene-Early Miocene. Eastward expansion of the lineage range proceeded from the western Mediterranean and involved colonization of mountain ranges in northern Africa. The phylogeography of the N. tazetta group revealed a widespread distribution of certain haplotypes, suggesting wide dispersal and a high level of colonization in the Mediterranean Basin. Main conclusions Our study points to the role of three key historical events in Narcissus diversification: tectonic shifts of the Alboran domain in the western Mediterranean, the Messinian salinity crisis, and the onset of the Mediterranean climate followed by periods of repeated glaciation. Diversification of section Apodanthi probably resulted from allopatric speciation, while subgenus Hermione may have shown more sympatric speciation and high dispersal, despite the lack of apparent adaptations to long-distance dispersal. This is best exemplified by the presence of both ancestral and recent haplotypes of N. tazetta across the Mediterranean. © 2011 Blackwell Publishing Ltd.

Suarez de Vivero J.L.,University of Seville | Rodriguez Mateos J.C.,University of Seville
Marine Policy | Year: 2012

The coming into effect of the Directive 2008/56/EC (Marine Strategy Framework Directive (MSFD)) will induce European Union member States to create mechanisms for managing maritime space in order to comply with the goals set out in this binding legislation. This leads one to think that marine spatial planning in various countries in the EU will be directed at complying with the Directive's environmental goals, as is the case in Spain, rather than undertaking proactive planning for developing the maritime sectors. To put the case of Spain into perspective, a review is conducted of the initiatives taken, especially in Europe and the European Union, exploring the correlations between the main focuses of the maritime sectors and the planning systems. The analysis of the Spanish initiative demonstrates how the maritime economy model and geopolitical factors explain the planning options for the marine environment. In other respects, with the coming into effect of the MSFD, a dual institutional course for marine spatial planning seems to be opening up in the EU: Integrated Maritime Policy vs. the Marine Strategy Framework Directive. © 2011 Elsevier Ltd.

In the phase III PARAMOUNT trial, pemetrexed continuation maintenance therapy reduced the risk of disease progression versus placebo (hazard ratio [HR], 0.62; 95% CI, 0.49 to 0.79; P < .001). Here we report final overall survival (OS) and updated safety data. In all, 939 patients with advanced nonsquamous non-small-cell lung cancer (NSCLC) received four cycles of pemetrexed-cisplatin induction therapy; then, 539 patients with no disease progression and Eastern Cooperative Oncology Group performance status 0 or 1 were randomly assigned (2:1) to maintenance pemetrexed (500 mg/m(2) on day 1 of 21-day cycles; n = 359) or placebo (n = 180). Log-rank test compared OS between arms as measured from random assignment (α = .0498). The mean number of maintenance cycles was 7.9 (range, one to 44) for pemetrexed and 5.0 (range, one to 38) for placebo. After 397 deaths (pemetrexed, 71%; placebo, 78%) and a median follow-up of 24.3 months for alive patients (95% CI, 23.2 to 25.1 months), pemetrexed therapy resulted in a statistically significant 22% reduction in the risk of death (HR, 0.78; 95% CI, 0.64 to 0.96; P = .0195; median OS: pemetrexed, 13.9 months; placebo, 11.0 months). Survival on pemetrexed was consistently improved for all patient subgroups, including induction response: complete/partial responders (n = 234) OS HR, 0.81; 95% CI, 0.59 to 1.11 and stable disease (n = 285) OS HR, 0.76; 95% CI, 0.57 to 1.01). Postdiscontinuation therapy use was similar: pemetrexed, 64%; placebo, 72%. No new safety findings emerged. Drug-related grade 3 to 4 anemia, fatigue, and neutropenia were significantly higher in pemetrexed-treated patients. Pemetrexed continuation maintenance therapy is well-tolerated and offers superior OS compared with placebo, further demonstrating that it is an efficacious treatment strategy for patients with advanced nonsquamous NSCLC and good performance status who did not progress during pemetrexed-cisplatin induction therapy.

Gonzalez de Molina F.J.,University of Barcelona | Leon C.,University of Seville | Ruiz-Santana S.,University of Las Palmas de Gran Canaria | Saavedra P.,University of Las Palmas de Gran Canaria
Critical Care | Year: 2012

Introduction: Candidemia in critically ill patients is usually a severe and life-threatening condition with a high crude mortality. Very few studies have focused on the impact of candidemia on ICU patient outcome and attributable mortality still remains controversial. This study was carried out to determine the attributable mortality of ICU-acquired candidemia in critically ill patients using propensity score matching analysis.Methods: A prospective observational study was conducted of all consecutive non-neutropenic adult patients admitted for at least seven days to 36 ICUs in Spain, France, and Argentina between April 2006 and June 2007. The probability of developing candidemia was estimated using a multivariate logistic regression model. Each patient with ICU-acquired candidemia was matched with two control patients with the nearest available Mahalanobis metric matching within the calipers defined by the propensity score. Standardized differences tests (SDT) for each variable before and after matching were calculated. Attributable mortality was determined by a modified Poisson regression model adjusted by those variables that still presented certain misalignments defined as a SDT > 10%.Results: Thirty-eight candidemias were diagnosed in 1,107 patients (34.3 episodes/1,000 ICU patients). Patients with and without candidemia had an ICU crude mortality of 52.6% versus 20.6% (P < 0.001) and a crude hospital mortality of 55.3% versus 29.6% (P = 0.01), respectively. In the propensity matched analysis, the corresponding figures were 51.4% versus 37.1% (P = 0.222) and 54.3% versus 50% (P = 0.680). After controlling residual confusion by the Poisson regression model, the relative risk (RR) of ICU- and hospital-attributable mortality from candidemia was RR 1.298 (95% confidence interval (CI) 0.88 to 1.98) and RR 1.096 (95% CI 0.68 to 1.69), respectively.Conclusions: ICU-acquired candidemia in critically ill patients is not associated with an increase in either ICU or hospital mortality. © 2012 González de Molina et al.; licensee BioMed Central Ltd.

Garcia-Quintanilla M.,University of Seville | Pulido M.R.,University of Seville | Lopez-Rojas R.,University of Seville | Pachon J.,University of Seville | McConnell M.J.,University of Seville
Trends in Microbiology | Year: 2013

The global emergence of multidrug resistant Acinetobacter baumannii has reduced the number of clinically available antibiotics that retain activity against this pathogen. For this reason, the development of novel prevention and treatment strategies for infections caused by A. baumannii is necessary. Several studies have begun to characterize nonantibiotic approaches that utilize novel mechanisms of action to achieve antibacterial activity. Recent advances in phage therapy, iron chelation therapy, antimicrobial peptides, prophylactic vaccination, photodynamic therapy, and nitric oxide (NO)-based therapies have all been shown to have activity against A. baumannii. However, before these approaches can be used clinically there are still limitations and remaining questions that must be addressed. © 2012 Elsevier Ltd.

Garcia-Carbonero R.,University of Seville | Garcia-Carbonero R.,Hospital Universitario Virgen del Rocio | Carnero A.,University of Seville | Paz-Ares L.,University of Seville | Paz-Ares L.,Hospital Universitario Virgen del Rocio
The Lancet Oncology | Year: 2013

Heat shock protein 90 (HSP90) is a molecular chaperone that is crucial for the stability and function of many proteins essential for cell survival. Many oncogenes, including tyrosine kinases, transcription factors, and cell-cycle regulatory proteins, are client proteins of HSP90. Inhibition of HSP90 causes client protein degradation via the ubiquitin-proteasome pathway, and is a mechanism that might simultaneously downregulate several redundant pathways crucial for cell viability and tumour development. HSP90 inhibitors are currently being developed as anticancer agents, and have shown early promising results in molecularly defined subgroups of solid tumours (eg, ALK-rearranged non-small-cell lung cancer and HER2-amplified breast cancer) and some haematological malignancies (eg, multiple myeloma). Here, we review the current status of HSP90 inhibitors in clinical development, including geldanamycin derivatives, resorcinol derivatives, purine analogues, and other synthetic inhibitors. We also discuss novel strategies and future perspectives on how to optimise the therapeutic potential of this exciting new class of drugs. © 2013 Elsevier Ltd.

Colomer M.A.,University of Lleida | Margalida A.,University of Bern | Perez-Jimenez M.J.,University of Seville
PLoS ONE | Year: 2013

Today, the volume of data and knowledge of processes necessitates more complex models that integrate all available information. This handicap has been solved thanks to the technological advances in both software and hardware. Computational tools available today have allowed developing a new family of models, known as computational models. The description of these models is difficult as they can not be expressed analytically, and it is therefore necessary to create protocols that serve as guidelines for future users. The Population Dynamics P systems models (PDP) are a novel and effective computational tool to model complex problems, are characterized by the ability to work in parallel (simultaneously interrelating different processes), are modular and have a high computational efficiency. However, the difficulty of describing these models therefore requires a protocol to unify the presentation and the steps to follow. We use two case studies to demonstrate the use and implementation of these computational models for population dynamics and ecological process studies, discussing briefly their potential applicability to simulate complex ecosystem dynamics. © 2013 Colomer et al.

Vazquez R.,University of Seville | Krstic M.,University of California at San Diego
Systems and Control Letters | Year: 2014

We find the exact analytical solution to a Goursat PDE system governing the kernels of a backstepping-based boundary control law that stabilizes a constant-coefficient 2×2 system of first-order hyperbolic linear PDEs. The solution to the Goursat system is related to the solution of a simpler, explicitly solvable Goursat system through a suitable infinite series of powers of partial derivatives which is summed explicitly in terms of special functions, including Bessel functions and the generalized Marcum Q-functions of the first order. The Marcum functions are common in certain applications in communications but have not appeared previously in control design problems. The dependence of the explicit solutions with respect to system parameters is analyzed through several examples, including the stabilization of a constant equilibrium for a quasi-linear plant. © 2014 Elsevier B.V. All rights reserved.

Borrego D.,University of Seville | Barba I.,University of Seville
Expert Systems with Applications | Year: 2014

A business process (BP) consists of a set of activities which are performed in coordination in an organizational and technical environment and which jointly realize a business goal. In such context, BP management (BPM) can be seen as supporting BPs using methods, techniques, and software in order to design, enact, control, and analyze operational processes involving humans, organizations, applications, and other sources of information. Since the accurate management of BPs is receiving increasing attention, conformance checking, i.e.; verifying whether the observed behavior matches a modelled behavior, is becoming more and more critical. Moreover, declarative languages are more frequently used to provide an increased flexibility. However, whereas there exist solid conformance checking techniques for imperative models, little work has been conducted for declarative models. Furthermore, only control-flow perspective is usually considered although other perspectives (e.g.; data) are crucial. In addition, most approaches exclusively check the conformance without providing any related diagnostics. To enhance the accurate management of flexible BPs, this work presents a constraint-based approach for conformance checking over declarative BP models (including both control-flow and data perspectives). In addition, two constraint-based proposals for providing related diagnosis are detailed. To demonstrate both the effectiveness and the efficiency of the proposed approaches, the analysis of different performance measures related to a wide diversified set of test models of varying complexity has been performed. © 2014 Elsevier Ltd. All rights reserved.

Castillo-Manzano J.I.,University of Seville | Castro-Nuno M.,University of Seville | Fageda X.,University of Barcelona
European Journal of Health Economics | Year: 2014

This study uses data for the EU-27 countries in the period 1999-2009 to estimate determinants of road traffic fatality rates. Controlling for country attributes and road safety policy variables, we examine the influence of variables related with the national health systems; the number of hospital beds per square kilometer, and the percentage of health expenditures over gross domestic product. We find evidence that the density of hospital beds contributes to the fall in traffic-related fatalities. Furthermore, the quality of general medical facilities and technology associated with increases in health expenditure may be also a relevant factor in reducing road traffic fatalities. © 2013 Springer-Verlag.

Talero E.,University of Seville | Garcia-Maurino S.,University of Seville | Motilva V.,University of Seville
Current Pharmaceutical Design | Year: 2014

The intestinal epithelium forms a barrier against the intestinal contents and the wider environment, allowing entry of selected molecules for nutrition and programming of the mucosal immune system, but excluding toxins and most microorganisms. Many receptors and signalling pathways are coupled and implicated in the epithelial control and significant advances have been achieved in the understanding of the pathogenesis of inflammatory bowel disease (IBD) and in the introduction of biologics. However, not all of the patients respond and many lose their response. Data from experimental studies have documented that the pineal secretory product melatonin exerts important inmunoregulatory and antiinflammatory effects in different models of colitis. These actions have been associated to a variety of mechanisms, such as reduction of T cells number, modulation of macrophage activity, suppression of NFkB activity, inhibition of cell adhesion molecules and proinflammatory cytokines, suppression of COX-2 and iNOS levels and the consequent synthesis of PGE2 and NO, reduction of matrix metalloprote-inase (MMP) -2 and -9 activity, and modulation of apoptosis. In addition, the beneficial effects of melatonin in IBD are related to its scavenger effect on free radicals and the activation of several antioxidant enzymes. However, only a small number of human studies report possible beneficial and also possible harmful effects of melatonin in case reports and clinical trials. There is a considerable bulk of information supporting the connection between autophagy and human diseases, including IBD, and although autophagy is actually considered more a pro-survival than a pro-death pathway, these two features of its action are relevant in human diseases, having therapeutic potential for both activators and inhibitors of autophagy. Some of the opposite effects than have been reported for melatonin in IBD could be related to the duality of its effects on autophagy, which itself can be beneficial or detrimental. In this review, new data for melatonin in IBD are discussed, trying to provide recent information of different molecular mechanism including the role of the autophagy regulation. © 2014 Bentham Science Publishers.