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Zaragoza, Spain

The University of Zaragoza, sometimes referred to as Saragossa University is a university located in Zaragoza, in the Aragon region of Spain. Founded in 1542, it is one of the oldest universities in Spain, with a history dating back to the Roman period. The university has over 40,000 students in its 22 faculties. The university is the only public university in the region. Its activity is spread along the three provinces of Aragon, with teaching campuses and research centres in Huesca, Teruel and Zaragoza. Wikipedia.

Gil J.J.,University of Zaragoza
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

The measured Mueller matrices contain until sixteen independent parameters for each measurement configuration (spectral profile of the wave probe of the polarimeter, angle of incidence, observation direction⋯) and for each spatially resolved element of the sample (imaging polarimetry). Thus, the polarimetric techniques are widely used for the study of a great variety of material samples in optics and remote sensing. Nevertheless, the relevant physical information does not appear explicitly in the measured parameters and thus the best knowledge of the structure of the physical information contained in a Mueller matrix is required in order to develop appropriate procedures for the polarimetric analysis. In this paper, the physically invariant polarimetric quantities are identified and decoupled, and the main approaches for serial and parallel decompositions of measured Mueller matrices into simple components are reviewed. © 2013 SPIE.

Rodriguez R.J.,University of Zaragoza
Automated Software Engineering | Year: 2015

Functional and non-functional properties analysis (i.e., dependability, security, or performance) ensures that requirements are fulfilled during the design phase of software systems. However, the Unified Modelling Language (UML), standard de facto in industry for software systems modelling, is unsuitable for any kind of analysis but can be tailored for specific analysis purposes through profiling. For instance, the MARTE profile enables to annotate performance data within UML models that can be later transformed to formal models (e.g., Petri nets or timed automatas) for performance evaluation. A performance (or throughput) estimation in such models normally relies on a whole exploration of the state space, which becomes unfeasible for large systems. To overcome this issue upper throughput bounds are computed, which provide an approximation to the real system throughput with a good complexity-accuracy trade-off. This paper introduces a tool, named PeabraiN, that estimates the performance of software systems via their UML models. To do so, UML models are transformed to Petri nets where performance is estimated based on upper throughput bounds computation. PeabraiN also allows to compute other features on Petri nets, such as the computation of upper and lower marking place bounds, and to simulate using an approximate (continuous) method. We show the applicability of PeabraiN by evaluating the performance of a building closed circuit TV system. © 2015 Springer Science+Business Media New York

Casellas J.,Autonomous University of Barcelona | Varona L.,University of Zaragoza
PLoS ONE | Year: 2012

Gene expression data are influenced by multiple biological and technological factors leading to a wide range of dispersion scenarios, although skewed patterns are not commonly addressed in microarray analyses. In this study, the distribution pattern of several human transcriptomes has been studied on free-access microarray gene expression data. Our results showed that, even in previously normalized gene expression data, probe and differential expression within probe effects suffer from substantial departures from the commonly assumed symmetric Gaussian distribution. We developed a flexible mixed model for non-competitive microarray data analysis that accounted for asymmetric and heavy-tailed (Student's t distribution) dispersion processes. Random effects for gene expression data were modeled under asymmetric Student's t distributions where the asymmetry parameter (λ) took values from perfect symmetry (λ = 0) to right- (λ>0) or left-side (λ>0) over-expression patterns. This approach was applied to four free-access human data sets and revealed clearly better model performance when comparing with standard approaches accounting for traditional symmetric Gaussian distribution patterns. Our analyses on human gene expression data revealed a substantial degree of right-hand asymmetry for probe effects, whereas differential gene expression addressed both symmetric and left-hand asymmetric patterns. Although these results cannot be extrapolated to all microarray experiments, they highlighted the incidence of skew dispersion patterns in human transcriptome; moreover, we provided a new analytical approach to appropriately address this biological phenomenon. The source code of the program accommodating these analytical developments and additional information about practical aspects on running the program are freely available by request to the corresponding author of this article. © 2012 Casellas, Varona.

Ranada M.F.,University of Zaragoza
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2015

Two important advances in integrability have been the recent discovery of the higher-order superintegrability of the Tremblay-Turbiner-Winternitz system (related to the harmonic oscillator) and the Post-Winternitz system (related to the Kepler problem). The properties of the TTW system have been recently studied on the two-dimensional spherical Sκ2 (κ>0) and hyperbolic Hκ2 (κ<0) spaces by making use of a curvature-dependent formalism and the existence of a complex factorization for the higher-order constant of motion. Now in this Letter we prove that a similar technique can also be applied for the study of the PW system. © 2015 Published by Elsevier B.V.

Bobillo F.,University of Zaragoza | Straccia U.,CNR Institute of Information Science and Technologies Alessandro Faedo
International Journal of Approximate Reasoning | Year: 2011

The need to deal with vague information in Semantic Web languages is rising in importance and, thus, calls for a standard way to represent such information. We may address this issue by either extending current Semantic Web languages to cope with vagueness, or by providing a procedure to represent such information within current standard languages and tools. In this work, we follow the latter approach, by identifying the syntactic differences that a fuzzy ontology language has to cope with, and by proposing a concrete methodology to represent fuzzy ontologies using OWL 2 annotation properties. We also report on some prototypical implementations: a plug-in to edit fuzzy ontologies using OWL 2 annotations and some parsers that translate fuzzy ontologies represented using our methodology into the languages supported by some reasoners. © 2011 Elsevier Inc. All rights reserved.

Bobillo F.,University of Zaragoza | Bou F.,University of Barcelona | Straccia U.,CNR Institute of Information Science and Technologies Alessandro Faedo
Fuzzy Sets and Systems | Year: 2011

Fuzzy Description Logics (DLs) are a family of logics which allow the representation of (and the reasoning with) structured knowledge affected by vagueness. Although most of the not very expressive crisp DLs, such as ALC, enjoy the Finite Model Property (FMP), this is not the case once we move into the fuzzy case. In this paper we show that if we allow arbitrary knowledge bases, then the fuzzy DLs ALC under Łukasiewicz and Product fuzzy logics do not verify the FMP even if we restrict to witnessed models; in other words, finite satisfiability and witnessed satisfiability are different for arbitrary knowledge bases. The aim of this paper is to point out the failure of FMP because it affects several algorithms published in the literature for reasoning under fuzzy DLs. © 2011 Elsevier B.V. All rights reserved.

We review the four main extinction events in the Paleogene, from the Cretaceous/Paleogene boundary to the Eocene/Oligocene boundary, integrating the results obtained from a study of foraminiferal assemblages with other paleontological and geological data. Different survival strategies followed by the species are described and the duration of the phases of extinction, survival, and recovery is estimated. The models and patterns of extinction of the foraminifera are highlighted. We present a range of evidence and paleo-environmental factors and analyze the possible causes of extinction. A new terminology for mass extinction events is proposed: sudden mass extinction would have happened virtually instantaneously and the process would have taken a few years or decades (Cretaceous/Paleogene boundary). Rapid mass extinction is defined as that which occurred in relatively short events, around 100. kyr (Paleocene/Eocene and Eocene/Oligocene boundaries). Slow mass extinctions are suggested to have lasted around 1. Myr (Bartonian/Priabonian transition) and may even have lasted for several million years. © 2014 Elsevier B.V.

Gil J.J.,University of Zaragoza
Journal of the European Optical Society | Year: 2015

The second-order characterization of a three-dimensional (3D) state of polarization is provided either by the corresponding 3D coherency matrix or (equivalently) by the associated 3D Stokes parameters. The analysis of the polarization properties that are invariant under orthogonal transformations of the laboratory reference frame allows to define a set of six intrinsic Stokes parameters which provides a simplified interpretation of 3D states of polarization in terms of meaningful physical properties. The rotationally invariant properties of 2D states of polarization are straightforwardly retrieved in a consistent way, so that the 2D intrinsic Stokes parameters are constituted by the intensity, the degree of linear polarization and the degree of circular polarization. © 2015, European Optical Society (EOS). All rights Reserved.

Galve F.,Campus University Illes Balears | Pachon L.A.,National University of Colombia | Zueco D.,University of Zaragoza
Physical Review Letters | Year: 2010

Decoherence due to contact with a hot environment typically restricts quantum phenomena to the low temperature limit, kBT/ω1 (ω is the typical energy of the system). Here we report the existence of a nonequilibrium state for two coupled, parametrically driven, dissipative harmonic oscillators which, contrary to generalized intuition, has stationary entanglement at high temperatures. This clarifies the role of temperature and could lighten the burden on quantum experiments requiring delicate precooling setups. © 2010 The American Physical Society.

De-Los-Santos A.,Polytechnic University of Valencia | Laporte G.,HEC Montreal | Mesa J.A.,Polytechnic University of Valencia | Perea F.,University of Zaragoza
Transportation Research Part C: Emerging Technologies | Year: 2012

The purpose of this paper is to provide passenger robustness measures for a rail transit network. A network is robust when it reacts well to disruptions on links or stations. In order to measure robustness, indexes relative to the overall travel time of a network when links fail are introduced for two different cases: without-bridging interruptions and with-bridging interruptions. In the first case, passengers either have to wait for the failure to be repaired or find an alternative route in the network, whereas in the second case a bus service between the affected stations is provided and only the failing link is disrupted. A computation of these indexes for the Madrid commuter system shows their applicability. © 2010 Elsevier Ltd.

Zhang Z.,CAS Institute of Geology and Geophysics | Yang L.,China University of Geosciences | Teng J.,CAS Institute of Geology and Geophysics | Badal J.,University of Zaragoza
Earth-Science Reviews | Year: 2011

We assess the results of a number of deep seismic soundings performed in China over the last few decades, and study the variations in crustal structure in 18 tectonic units comprised of three platforms and 15 fold systems. Thickness data on 344 Mesozoic-Cenozoic sedimentary basins, as well as data on Moho depth are collected in order to discuss the relationship between the thickness of the basins and the average thickness of the consolidated crust in each tectonic unit. The degree of mirror-image symmetry between Mesozoic-Cenozoic sedimentary basins and the uplifting topmost parts of the mantle is herein analyzed using deep geophysical data on sedimentary basins. By applying standard methods of least-squares analysis to both datasets, we have obtained both the average thickness of the consolidated crust and the mirror-image symmetry factor for every platform and tectonic fold system, thereby allowing us to explore the correlation between the depths of the bottom of the sedimentary basins and the top of the uplifting mantle. The thickness of the consolidated crust in China is found to be between 20 and 63. km, following a pattern of gradual thickening from east to west. Expressed in terms of spatial seismicity and the concentration of seismic energy, and according to the sharing-out of earthquake hypocenters in the top 80. km of the earth, the rheology of the area does not appear to suit the widely accepted "jelly-sandwich" model for the continents, which does not seem to be entirely valid in China. The findings on the mirror-image symmetry factor show that this parameter varies mainly in the range -0.5 to -1.8 compared with each other tectonic unit. Most of the tectonic systems in China appear to be isostatically compensated. Tibet is an exception, in that the symmetry factor is positive for the Gangdise-Nyainqentanglha (1.0) and Himalayan (0.1) fold systems, implying that these tectonic zones are far from being in the isostatic equilibrium of the other regions. We have also analyzed the zoning characteristics through the logarithmic relationship ln R=ln (h/|. a|), using the average thickness of the consolidated crust and the absolute value of the symmetry factor. The key finding is that regardless of geographical location, all the values of R= h/|a| for those sedimentary basins in which oil/gas reservoirs have to date been found, fall into the narrow range of values between 19.38 and 37.40. There is some appeal in a possible relationship involving the ratio of crustal thickness to symmetry factor, more so when the results obtained appear to suggest a prognostic tool for exploratory practice in relation to oil/gas reservoirs. © 2010 Elsevier B.V.

Aider M.,Laval University | Barbana C.,University of Zaragoza
Trends in Food Science and Technology | Year: 2011

There is a well-recognized connection between the use of plant proteins in functional foods, nutraceuticals and other natural health products and health promotion and disease risk reduction. Plant proteins are largely used in the food industry, and canola/rapeseed proteins are regarded as potential ingredients that may be used as food additives. In this review, the chemical composition (amino acids and protein fractions), production and isolation techniques, functional properties, allergenicity, food applications and potential uses of canola proteins for the production of bioactive compounds are highlighted. © 2010 Elsevier Ltd.

Aromi G.,University of Barcelona | Barrios L.A.,University of Barcelona | Roubeau O.,University of Zaragoza | Gamez P.,University of Barcelona
Coordination Chemistry Reviews | Year: 2011

The current great interest in preparing functional metal-organic materials is inevitably associated with tremendous research efforts dedicated to the design and synthesis of new families of sophisticated multi-nucleating ligands. In this context, the N-donor triazole and tetrazole rings represent two categories of ligands that are increasingly used, most likely as the result of the recent dramatic development of " click chemistry" and Zeolitic Imidazolate Frameworks (ZIFs). Thus, azole-based complexes have found numerous applications in coordination chemistry.In the present review, we focus on the utilization of 1,2,3-triazole, 1,2,4-triazole and tetrazole ligands to create coordination polymers, metal complexes and spin-crossover compounds, reported to the end of 2009. In the first instance, we present a compendium of all the relevant ligands that have been employed to generate coordination polymers and Metal-Organic Frameworks (MOFs). Due to the huge amount of reported MOFs and coordination polymers bearing these azole rings, three representative examples for each category (therefore nine in total) are described in detail. The second section is devoted to the use of the bridging abilities of these azole ligands to prepare metal complexes (containing at least two metal centers). Given the large number and the great structural diversity of the polynuclear compounds found in the literature, these have been grouped according to their nuclearity. Finally, in the last section, the triazole- and tetrazole-containing coordination compounds exhibiting spin-crossover properties are presented. © 2010 Elsevier B.V.

Stankiewicz J.,University of Zaragoza | Karpenkov D.,Tver State University | Skokov K.P.,Tver State University
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

We have measured the resistivity and Hall effect of R 2Fe 17 (R=Y, Tb, and Gd) single crystals in the temperature T range 4

Bobillo F.,University of Zaragoza | Straccia U.,CNR Institute of Neuroscience
Information Sciences | Year: 2012

Description logics (DLs) are a family of logics for representing structured knowledge which have proved to be very useful as ontology languages. Classical DLs are not suitable to represent vague pieces of information. The attempts to achieve a solution have led to the birth of fuzzy DLs and rough DLs. In this work, we provide a simple solution to join these two formalisms and define a fuzzy rough DL. This logic is more general than other related approaches, including tight and loose fuzzy rough approximations and being independent of the fuzzy logic operators considered. We show the usefulness of our approach by presenting some uses case, and we also describe how to extend two reasoning algorithms for fuzzy DLs, which are implemented in the fuzzy DL reasoners fuzzyDL and DeLorean. © 2011 Elsevier Inc. All rights reserved.

Inda L.A.,University of Zaragoza | Pimentel M.,University of La Coruna | Chase M.W.,Jodrell Laboratory
Annals of Botany | Year: 2012

Background and aimsTribe Orchideae (Orchidaceae: Orchidoideae) comprises around 62 mostly terrestrial genera, which are well represented in the Northern Temperate Zone and less frequently in tropical areas of both the Old and New Worlds. Phylogenetic relationships within this tribe have been studied previously using only nuclear ribosomal DNA (nuclear ribosomal internal transcribed spacer, nrITS). However, different parts of the phylogenetic tree in these analyses were weakly supported, and integrating information from different plant genomes is clearly necessary in orchids, where reticulate evolution events are putatively common. The aims of this study were to: (1) obtain a well-supported and dated phylogenetic hypothesis for tribe Orchideae, (ii) assess appropriateness of recent nomenclatural changes in this tribe in the last decade, (3) detect possible examples of reticulate evolution and (4) analyse in a temporal context evolutionary trends for subtribe Orchidinae with special emphasis on pollination systems.MethodsThe analyses included 118 samples, belonging to 103 species and 25 genera, for three DNA regions (nrITS, mitochondrial cox1 intron and plastid rpl16 intron). Bayesian and maximum-parsimony methods were used to construct a well-supported and dated tree. Evolutionary trends in the subtribe were analysed using Bayesian and maximum-likelihood methods of character evolution.Key ResultsThe dated phylogenetic tree strongly supported the recently recircumscribed generic concepts of Bateman and collaborators. Moreover, it was found that Orchidinae have diversified in the Mediterranean basin during the last 15 million years, and one potential example of reticulate evolution in the subtribe was identified. In Orchidinae, pollination systems have shifted on numerous occasions during the last 23 million years.ConclusionsThe results indicate that ancestral Orchidinae were hymenopteran-pollinated, food-deceptive plants and that these traits have been dominant throughout the evolutionary history of the subtribe in the Mediterranean. Evidence was also obtained that the onset of sexual deception might be linked to an increase in labellum size, and the possibility is discussed that diversification in Orchidinae developed in parallel with diversification of bees and wasps from the Miocene onwards. © The Author 2012. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.

Parmentier H.,General Practitioner | Garcia-Campayo J.,University of Zaragoza | Prieto R.,Pfizer
Current Medical Research and Opinion | Year: 2013

Objective: This review aims to summarize meta-analyses and other relevant data relating to the efficacy and safety of the various treatment options for generalized anxiety disorder (GAD) in Europe. In addition, it will provide an overview of the prevalence, burden, and recognition of the disorder, with a view to raise awareness of GAD and inform primary care practitioners. Research design and methods: Relevant research or review articles on psychological or pharmacological treatments for GAD published in the English language between March 2006 and March 2012 were identified via a literature search in PubMed and ISI Web of Knowledge and from the Cochrane Library. Other relevant references/clinical guidelines were individually selected by the authors. Results: Prevalence rates of GAD vary across Europe but its economic and social burden is increasing. A large proportion of patients with GAD present with symptoms in primary care. However, due to the disorder's complexity and the incidence of comorbid diseases, some primary care physicians may lack the knowledge or confidence to effectively recognize, manage, and/or treat the disorder. This is despite psychological and pharmacological treatments being available for the effective management of GAD. Conclusions: GAD remains a difficult disorder to detect and comorbid complications add to its economic and social burden. Early detection and intervention reduces the societal burden and improves GAD patients' quality of life and functional ability. Primary care practitioners play a key role in identifying and treating patients with GAD. © 2013 Informa UK Ltd All rights reserved.

Navarro R.,University of Zaragoza
Journal of Vision | Year: 2010

The problem of measuring the objective refractive error with an aberrometer has shown to be more elusive than expected. Here, the formalism of differential geometry is applied to develop a theoretical framework of refractive error sensing. At each point of the pupil, the local refractive error is given by the wavefront curvature, which is a 2 × 2 symmetric matrix, whose elements are directly related to sphere, cylinder, and axis. Aberrometers usually measure the local gradient of the wavefront. Then refractive error sensing consists of differentiating the gradient, instead of integrating as in wavefront sensing. A statistical approach is proposed to pass from the local to the global (clinically meaningful) refractive error, in which the best correction is assumed to be the maximum likelihood estimation. In the practical implementation, this corresponds to the mode of the joint histogram of the 3 different elements of the curvature matrix. Results obtained both in computer simulations and with real data provide a close agreement and consistency with the main optical image quality metrics such as the Strehl ratio. © ARVO.

Fandos-Herrera C.,University of Zaragoza
Spanish Journal of Agricultural Research | Year: 2016

The growing concern about quality in food products has substantially increased the competitiveness of agro-food products that possess quality-system certifications compared to non-certificated products. This research focused on understanding how consumer trust is greater when agro-food products have a Protected Designation of Origin (PDO). In particular, we analyze whether the influence of consumers’ perceived quality of a PDO product has a direct effect on their perceived risk or whether this relationship is mediated by consumer trust, which can help us advance in the study of consumer behavior within the agro-food marketing discipline. Our findings obtained through the comparison of two models, the proposal and another rival, suggest that the initially proposed model present a better fit and explains the relationships better than the rival model, which highlights the essential role of consumer trust in explaining consumers’ perceived risk and their subsequent purchasing behavior. Consequently, managers should pay special attention to consumer trust because trust is the key mediating aspect which allows the incorporation of characteristics highly valued by consumers in food products like origin, tradition and production methods to reduce perceived risk. © 2016 INIA.

Greynat D.,University of Zaragoza | De Rafael E.,French National Center for Scientific Research | De Rafael E.,Universites Aix Marseille 1
Journal of High Energy Physics | Year: 2012

The hadronic contributions to the anomalous magnetic moment of the muon which are relevant for the confrontation between theory and experiment at the present level of accuracy, are evaluated within the same framework: the constituent chiral quark model. This includes the contributions from the dominant hadronic vacuum polarization as well as from the next-to-leading order hadronic vacuum polarization, the contributions from the hadronic light-by-light scattering, and the contributions from the electroweak hadronic Zγγ vertex. They are all evaluated as a function of only one free parameter: the constituent quark mass. We also comment on the comparison between our results and other phenomenological evaluations.

Hernandez M.,University of Zaragoza
Physics in Medicine and Biology | Year: 2014

In this work, we propose a novel preconditioned optimization method in the paradigm of Large Deformation Diffeomorphic Metric Mapping (LDDMM). The preconditioned update scheme is formulated for the non-stationary and the stationary parameterizations of diffeomorphisms, yielding three different LDDMM methods. The preconditioning matrices are inspired in the Hessian approximation used in Gauss-Newton method. The derivatives are computed using Frechet differentials. Thus, optimization is performed in a Sobolev space, in contrast to optimization in L2commonly used in non-rigid registration literature. The proposed LDDMM methods have been evaluated and compared with their respective implementations of gradient descent optimization. Evaluation has been performed using real and simulated images from the Non-rigid Image Registration Evaluation Project (NIREP). The experiments conducted in this work reported that our preconditioned LDDMM methods achieved a performance similar or superior to well-established-in-literature gradient descent non-stationary LDDMM in the great majority of cases. Moreover, preconditioned optimization showed a substantial reduction in the execution time with an affordable increase of the memory usage per iteration. Additional experiments reported that optimization using Frechet differentials should be preferable to optimization using L2differentials. © 2014 Institute of Physics and Engineering in Medicine.

Diaz F.,University of Miami | Enriquez J.A.,Centro National Of Investigaciones Cardiovasculares Carlos Iii | Enriquez J.A.,University of Zaragoza | Moraes C.T.,University of Miami
Molecular and Cellular Biology | Year: 2012

Mitochondrial respiratory complexes of the electron transport chain (CI, CIII, and CIV) can be assembled into larger structures forming supercomplexes. We analyzed the assembly/stability of respiratory complexes in mouse lung fibroblasts lacking the Rieske iron-sulfur protein (RISP knockout [KO]cells), one of the catalytic subunits of CIII. In the absence of RISP, most of the remaining CIII subunits were able to assemble into a large precomplex that lacked enzymatic activity. CI, CIV, and supercomplexes were decreased in the RISP-deficient cells. Reintroduction of RISP into KO cells restored CIII activity and increased the levels of active CI, CIV, and supercomplexes. We found that hypoxia (1% O 2) resulted in increased levels of CI, CIV, and supercomplex assembly in RISP KO cells. In addition, treatment of control cells with different oxidative phosphorylation (OXPHOS) inhibitors showed that compounds known to generate reactive oxygen species (ROS) (e.g., antimycin A and oligomycin) had a negative impact on CI and supercomplex levels. Accordingly, a superoxide dismutase (SOD) mimetic compound and SOD2 overexpression provided a partial increase in supercomplex levels in the RISP KO cells. Our data suggest that the stability of CI, CIV, and supercomplexes is regulated by ROS in the context of defective oxidative phosphorylation. © 2012, American Society for Microbiology.

Ebrahimi-Fard K.,University of Zaragoza | Patras F.,French National Center for Scientific Research
Annales Henri Poincare | Year: 2010

Moving beyond the classical additive and multiplicative approaches, we present an "exponential" method for perturbative renormalization. Using Dyson's identity for Green's functions as well as the link between the Faà di Bruno Hopf algebra and the Hopf algebras of Feynman graphs, its relation to the composition of formal power series is analyzed. Eventually, we argue that the new method has several attractive features and encompasses the BPHZ method. The latter can be seen as a special case of the new procedure for renormalization scheme maps with the Rota-Baxter property. To our best knowledge, although very natural from group-theoretical and physical points of view, several ideas introduced in the present paper seem to be new (besides the exponential method, let us mention the notions of counter-factors and of order n bare coupling constants). © 2010 Springer Basel AG.

Munguia-Izquierdo D.,Pablo De Olavide University | Legaz-Arrese A.,University of Zaragoza
Archives of Physical Medicine and Rehabilitation | Year: 2012

Objective: To evaluate the reliability, standard error of the mean (SEM), clinical significant change, and known group validity of 2 assessments of endurance strength to low loads in patients with fibromyalgia syndrome (FS). Design: Cross-sectional reliability and comparative study. Setting: University Pablo de Olavide, Seville, Spain. Participants: Middle-aged women with FS (n=95) and healthy women (n=64) matched for age, weight, and body mass index (BMI) were recruited for the study. Interventions: Not applicable. Main Outcome Measures: The endurance strength to low loads tests of the upper and lower extremities and anthropometric measures (BMI) were used for the evaluations. The differences between the readings (tests 1 and 2) and the SDs of the differences, intraclass correlation coefficient (ICC) model (2,1), 95% confidence interval for the ICC, coefficient of repeatability, intrapatient SD, SEM, Wilcoxon signed-rank test, and Bland-Altman plots were used to examine reliability. A Mann-Whitney U test was used to analyze the differences in test values between the patient group and the control group. We hypothesized that patients with FS would have an endurance strength to low loads performance in lower and upper extremities at least twice as low as that of the healthy controls. Results: Satisfactory test-retest reliability and SEMs were found for the lower extremity, dominant arm, and nondominant arm tests (ICC=.973-.979; P<.001; SEMs=1.44-1.66 repetitions). The differences in the mean between the test and retest were lower than the SEM for all performed tests, varying from -.10 to.29 repetitions. No significant differences were found between the test and retest (P>.05 for all). The Bland-Altman plots showed 95% limits of agreement for the lower extremity (4.7 to -4.5), dominant arm (3.8 to -4.4), and nondominant arm (3.9 to -4.1) tests. The endurance strength to low loads test scores for the patients with FS were 4-fold lower than for the controls in all performed tests (P<.001 for all). Conclusions: The endurance strength to low loads tests showed good reliability and known group validity and can be recommended for evaluating endurance strength to low loads in patients with FS. For individual evaluation, however, an improved score of at least 4 and 5 repetitions for the upper and lower extremities, respectively, was required for the differences to be considered as substantial clinical change. Patients with FS showed impaired endurance strength to low loads performance when compared with the general population. © 2012 American Congress of Rehabilitation Medicine.

Cenerario N.,Lille Laboratory of Mechanics | Delot T.,Lille Laboratory of Mechanics | Ilarri S.,University of Zaragoza
IEEE Transactions on Intelligent Transportation Systems | Year: 2011

This paper focuses on intelligent transportation systems and, more precisely, on intervehicle ad hoc networks. A vehicular ad hoc network (VANET) is a highly dynamic network as the vehicles communicate using short-range wireless communications and can move very quickly. Thus, for example, we can only rely on short interactions between vehicles to exchange information about relevant events. In this paper, we describe in detail a dissemination protocol that vehicles can use to share information by using vehicle-to-vehicle communications. The dissemination approach considers the relevance of the data, represented by what we call encounter probability, to decide when a rediffusion is needed. The protocol is able to disseminate data about any type of event in the network (e.g., available parking spaces, accidents or obstacles in the road, information about moving objects such as emergency vehicles that should get the right of way, etc.) by setting appropriate weights for the different factors that affect the computation of the encounter probability. An extensive experimental evaluation with different types of events shows the interest of the proposal: The vehicles receive the relevant messages in time, and the network overload is limited. © 2006 IEEE.

Hirner A.V.,University of Zaragoza
Metal ions in life sciences | Year: 2010

While the metal(loid)s arsenic, bismuth, and selenium (probably also tellurium) have been shown to be enzymatically methylated in the human body, this has not yet been demonstrated for antimony, cadmium, germanium, indium, lead, mercury, thallium, and tin, although the latter elements can be biomethylated in the environment. Methylated metal(loid)s exhibit increased mobility, thus leading to a more efficient metal(loid) transport within the body and, in particular, opening chances for passing membrane barriers (blood-brain barrier, placental barrier). As a consequence human health may be affected. In this review, relevant data from the literature are compiled, and are discussed with respect to the evaluation of assumed and proven health effects caused by alkylated metal(loid) species.

Martin S.,University of Liverpool | Martin S.,University of Zaragoza | Haiss W.,University of Liverpool | Higgins S.J.,University of Liverpool | Nichols R.J.,University of Liverpool
Nano Letters | Year: 2010

The single molecule conductance of the E and Z isomers of 4,4′-(ethene-1,2-diyl)dibenzoic acid has been determined using two scanning tunneling microscopy (STM) methods for forming molecular break junctions [the I(s) (I = current and s is distance) method and the in situ break junction technique]. Isomerization leads to significant changes in the electrical conductance of these molecules, with the Z isomer exhibiting a higher conductance than the E isomer. Isomerization is achieved directly on the gold surface through photoirradiation, and the STM is used to determine conductance before and after irradiation; reversible switching between the two isomers could be achieved through irradiation of the surface bound species at different wavelengths. In addition, three groups of molecular conductance values [A ("low"), B ("medium"), and C ("high")] have been measured for these carboxylate-terminated molecules. The origin of these conductance groups as well as the increase of the conductance for the Z isomer have been analyzed by comparing the length of the molecules extended in the gap, derived from molecular modeling, with the experimentally observed break-off distance for both isomers. © 2010 American Chemical Society.

Gil J.J.,University of Zaragoza | Jose I.S.,Instituto Aragones Of Estadistica
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2013

A general formulation of the additive composition and decomposition of Mueller matrices is presented, which is expressed in adequate terms for properly performing the "polarimetric subtraction," from a given depolarizing Mueller matrix M, of the Mueller matrix of a given nondepolarizing component that is incoherently embedded in the whole system represented byM. A general and comprehensive procedure for the polarimetric subtraction of depolarizing Mueller matrices is also developed. © 2013 Optical Society of America.

Gil J.J.,University of Zaragoza
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2013

The passivity of the linear components in the main approaches for serial decompositions of depolarizing Mueller matrices [J. Opt. Soc. Am. A 13, 1106 (1996); J. Opt. Soc. Am. A 26, 1109 (2009)] is dealt with, and it is found that it is not always possible to perform such decompositions in terms of passive components. A compact form of Mueller matrix ("arrow matrix") associated with any given Mueller matrix, which retains, in a condensed manner, the physical properties relative to transmittance, diattenuation, polarizance, and depolarization, is presented. © 2013 Optical Society of America.

Peropadre B.,Institute Fisica Fundamental IFF CSIC | Zueco D.,University of Zaragoza | Porras D.,Complutense University of Madrid | Porras D.,University of Sussex | Garcia-Ripoll J.J.,Institute Fisica Fundamental IFF CSIC
Physical Review Letters | Year: 2013

The time and space resolved dynamics of a qubit with an Ohmic coupling to propagating 1D photons is studied, from weak coupling to the ultrastrong coupling regime. A nonperturbative study based on matrix product states shows the following results, (i) The ground state of the combined systems contains excitations of both the qubit and the surrounding bosonic field. (ii) An initially excited qubit equilibrates through spontaneous emission to a state, which under certain conditions is locally close to that ground state, both in the qubit and the field. (iii) The resonances of the combined qubit-photon system match those of the spontaneous emission process and also the predictions of the adiabatic renormalization [A. J. Leggett et al., Rev. Mod. Phys. 59, 1 (1987)]. Finally, nonperturbative ab initio calculations show that this physics can be studied using a flux qubit galvanically coupled to a superconducting transmission line. © 2013 American Physical Society.

Diaz J.A.,University of Granada | Navarro R.,University of Zaragoza
Applied Optics | Year: 2014

We generalize the analytical form of the orthonormal elliptical polynomials for any arbitrary aspect ratio to arbitrary orientation and give expression for them up to the 4th order. The utility of the polynomials is demonstrated by obtaining the expansion up to the 8th order in two examples of an off-axis wavefront exiting from an optical system with a vignetted pupil. © 2014 Optical Society of America.

Gil J.J.,University of Zaragoza | Jose I.S.,Instituto Aragones Of Estadistica | Ossikovski R.,Ecole Polytechnique - Palaiseau
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2013

The algebraic methods for serial and parallel decompositions of Mueller matrices are combined in order to obtain a general framework for a suitable analysis of polarimetric measurements based on equivalent systems constituted by simple components. A general procedure for the parallel decomposition of a Mueller matrix into a convex sum of pure elements is presented and applied to the two canonical forms of depolarizing Mueller matrices [Ossikovski, J. Opt. Soc. Am. A 27, 123 (2010).], leading to the serial-parallel decomposition of any Mueller matrix. The resultant model is consistent with the mathematical structure and the reciprocity properties of Mueller matrices. © 2012 Optical Society of America.

Gil J.J.,University of Zaragoza | Jose I.S.,Instituto Aragones Of Estadistica
Optics Letters | Year: 2014

A general explicit algebraic characterization of Mueller matrices is presented in terms of the non-negativity of a set of leading principal minors of the coherency matrix CA associated with the arrow formMA of a given Mueller matrix M. This result is also formulated through a set of four characteristic Stokes vectors. The particular cases of Mueller matrices with zero degree of polarizance and symmetric Mueller matrices are analyzed. © 2014 Optical Society of America.

Salgado-Remacha F.J.,University of Zaragoza
Applied Optics | Year: 2014

The lack of intensity in the central region of Laguerre-Gaussian beams reduces their applicability as illumination sources. For this reason, it is usual to shape a Laguerre-Gaussian beam to a nearly Gaussian beam using a binary phase mask. The behavior of this rectified Laguerre-Gaussian beam is analyzed in this work in the Fresnel regime. A comparison between diverse Laguerre-Gaussian beams with rectified Laguerre-Gaussian beams shows that there appear two different regions along the propagation axis: first is a transition region (for lower distances) with a flat intensity distribution, and next is a second region (for longer distances) where the rectified Laguerre-Gaussian tends to a Gaussian shape. The results of this work are very valuable for the use of this kind of beam in microoptical applications. © 2014 Optical Society of America.

Puig L.,University of Pennsylvania | Guerrero J.J.,University of Zaragoza | Daniilidis K.,University of Pennsylvania
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2014

In this paper we propose a new approach to compute the scale space of any central projection system, such as catadioptric, fisheye or conventional cameras. Since these systems can be explained using a unified model, the single parameter that defines each type of system is used to automatically compute the corresponding Riemannian metric. This metric, is combined with the partial differential equations framework on manifolds, allows us to compute the Laplace-Beltrami (LB) operator, enabling the computation of the scale space of any central projection system. Scale space is essential for the intrinsic scale selection and neighborhood description in features like SIFT. We perform experiments with synthetic and real images to validate the generalization of our approach to any central projection system. We compare our approach with the best-existing methods showing competitive results in all type of cameras: catadioptric, fisheye, and perspective. © 1979-2012 IEEE.

Focks J.J.,Radboud University Nijmegen | Brouwer M.A.,Radboud University Nijmegen | Van Oijen M.G.H.,University Utrecht | Van Oijen M.G.H.,University of California at Los Angeles | And 3 more authors.
Heart | Year: 2013

Background Clopidogrel as an adjunct to aspirin has improved outcomes after acute coronary syndromes, but laboratory studies suggest a reduced antiplatelet effect when proton pump inhibitors (PPIs) are co-administered. Despite corroborating data from retrospective studies, new clinical data fuel the controversy on this issue. Purpose Systematic review of the impact of the addition of PPIs to clopidogrel on platelet function and cardiovascular outcome. Data sources PubMed, Web-of-Science, Cochrane Database and reference lists of related articles. Study selection Published articles on controlled studies addressing the addition of PPIs to clopidogrel. Platelet function studies describe patients as well as healthy volunteers. Clinical studies concern patients using clopidogrel for acute coronary syndromes or because of stent implantation for stable coronary disease. Data extraction Two investigators independently reviewed the identified articles for eligibility, and one author extracted the data. Data synthesis In 70% (7/10) of the laboratory studies examining healthy volunteers on clopidogrel, addition of PPIs resulted in a significant reduction in platelet inhibition. For patients, this was observed in 11/ 18 (61%) studies. The 33 clinical studies showed significant heterogeneity in observed outcomes, with risk ratios for major adverse cardiovascular events varying from 0.64 to 4.58 in the case of PPI use, which was randomly allocated in only two studies. Consequently, imbalances between prognosticators at baseline and PPI prescription bias markedly contributed to the variability in results. Conclusions Despite indications of reduced antiplatelet activity ex vivo in the case of PPI administration in clopidogrel users, data on the clinical consequences are controversial. With the accumulating evidence from better designed, prospective clinical studies, an adverse effect of PPI use on clinical outcome in patients on clopidogrel cannot be substantiated. This review challenges the validity of conclusions based on quantitative analyses of predominantly non-randomised data.

Asorey M.,University of Zaragoza | Munoz-Castaneda J.M.,University of Leipzig
Nuclear Physics B | Year: 2013

The infrared behaviour of quantum field theories confined in bounded domains is strongly dependent on the shape and structure of space boundaries. The most significant physical effect arises in the behaviour of the vacuum energy. The Casimir energy can be attractive or repulsive depending on the nature of the boundary. We calculate the vacuum energy for a massless scalar field confined between two homogeneous parallel plates with the most general type of boundary conditions depending on four parameters. The analysis provides a powerful method to identify which boundary conditions generate attractive or repulsive Casimir forces between the plates. In the interface between both regimes we find a very interesting family of boundary conditions which do not induce any type of Casimir force. We also show that the attractive regime holds far beyond identical boundary conditions for the two plates required by the Kenneth-Klich theorem and that the strongest attractive Casimir force appears for periodic boundary conditions whereas the strongest repulsive Casimir force corresponds to anti-periodic boundary conditions. Most of the analysed boundary conditions are new and some of them can be physically implemented with metamaterials. © 2013 Elsevier B.V.

Navascues M.A.,University of Zaragoza
Complex Analysis and Operator Theory | Year: 2010

In the present article every complex square integrable function defined in a real bounded interval is approached by means of a complex fractal function. The approximation depends on a partition of the interval and a vectorial parameter of the iterated function system providing the fractal attractor. The original may be discontinuous or undefined in a set of zero measure. The fractal elements can modify the features of the originals, for instance their character of smooth or non-smooth. The properties of the operator mapping every function into its fractal analogue are studied in the context of the uniform and least square norms. In particular, the transformation provides a decomposition of the set of square integrable maps. An orthogonal system of fractal functions is constructed explicitly for this space. Sufficient conditions for the uniform convergence of the fractal series expansion corresponding to this basis are also deduced. The fractal approximation of real functions is obtained as a particular case. © 2009 Birkhäuser Verlag Basel/Switzerland.

Craig G.A.,University of Barcelona | Roubeau O.,University of Zaragoza | Aromi G.,University of Barcelona
Coordination Chemistry Reviews | Year: 2014

The area of spin crossover (SCO) attracts interest both on a fundamental level and in terms of potential applications for compounds displaying this phenomenon. A few families of Fe(II) complexes have become paramount for the advance of this topic, for example, compounds based on bis-pyrazolylpyridine (bpp) ligands. Here, we describe the versatile and rich SCO behaviour shown by the group of SCO compounds based on the related ligand 2,6-bis(pyrazol-3-yl)pyridine (L1) and its recently developed derivatives. The use of derivatives of L1 represents an advance, as prior to 2011, no functionalised L1-type ligands had been employed to obtain SCO systems. These compounds are highly sensitive to the anion and degree of solvation within their lattices, many of which have been observed through single crystal X-ray diffraction studies. The structural data that have been published in recent years has permitted a magneto-structural correlation to be described, which proves to nicely complement the properties shown by the family based on L1's regio-isomer, 2,6-bis(pyrazol-1-yl)pyridine. © 2014 Elsevier B.V.

Strasdat H.,Imperial College London | Davison A.J.,Imperial College London | Montiel J.M.M.,University of Zaragoza | Konolige K.,Willow Garage, Inc.
Proceedings of the IEEE International Conference on Computer Vision | Year: 2011

We present a novel and general optimisation framework for visual SLAM, which scales for both local, highly accurate reconstruction and large-scale motion with long loop closures. We take a two-level approach that combines accurate pose-point constraints in the primary region of interest with a stabilising periphery of pose-pose soft constraints. Our algorithm automatically builds a suitable connected graph of keyposes and constraints, dynamically selects inner and outer window membership and optimises both simultaneously. We demonstrate in extensive simulation experiments that our method approaches the accuracy of offline bundle adjustment while maintaining constant-time operation, even in the hard case of very loopy monocular camera motion. Furthermore, we present a set of real experiments for various types of visual sensor and motion, including large scale SLAM with both monocular and stereo cameras, loopy local browsing with either monocular or RGB-D cameras, and dense RGB-D object model building. © 2011 IEEE.

Hernandez-Ortega B.,University of Zaragoza
Technovation | Year: 2011

The aim of this paper is to shed light on the role of trust in the acceptance of a technology once the firm has already used it (post-use trust). First, we examine the drivers which encourage the firm to trust in a technology and, second, we study the consequences of trust in terms of firm performance and intentions to continue to use the technology. The drivers involve (1) perceptions experienced by the firm during the employment of the technology, (2) the influence of the firms trading partners and (3) the importance of the IT managers attitude towards the technology. The study focuses on the acceptance of e-invoicing in Spain and the sample consists of 100 early adopter firms who have perceptions and knowledge about this technology. Our findings clarify the relationship between trust and technology acceptance and have important implications about trust-building structures that could improve the application of technologies that are in the early stages of implementation. © 2011 Elsevier Ltd. All rights reserved.

Gutierrez L.,CSIC - Institute of Materials Science | Morales M.P.,CSIC - Institute of Materials Science | Lazaro F.J.,University of Zaragoza
Physical Chemistry Chemical Physics | Year: 2014

Methods for the quantitative determination of magnetic nanoparticles in biological matrices, in the frame of biomedical applications, are required to evaluate the particles biodistribution after systemic administration. AC magnetic susceptibility measurements are an alternative method to quantify magnetic nanoparticles in tissues, being able to provide also information on the particle transformations over time and allowing the distinction of the particles from other endogenous species such as the ferritin iron cores. The protocol for particle quantification using AC magnetic susceptibility measurements is described in detail in this article. A summary of synthesis routes towards magnetic nanoparticles is also provided. © 2014 the Owner Societies.

Miranda-de la Lama G.C.,University of Zaragoza | Mattiello S.,University of Milan
Small Ruminant Research | Year: 2010

The domestic goat is a sociable, inquisitive, and intelligent species, which has been used for its meat, milk, skin, and fur since it was first domesticated ca. 10,000 years ago. Although it exhibits a wide range of behaviours, the domesticated goat has been the subject of relatively few behavioural studies. In domestic goats, the opportunity to express certain social behaviours can be limited by captivity and management systems, especially in modern production systems, where goats are reared intensively under high stocking densities, sexual segregation, early separation of kids from their mothers, frequent regrouping, and manipulation during critical periods, including gestation and weaning. To better understand the requirements of this species and to identify possible tools for the detection of early modifications in natural behaviours that might indicate poor welfare and the establishment of positive human-animal interactions, this review provides a detailed description of goat social behaviour. Practical recommendations arising from observations of goat social behaviour are provided in the conclusions. © 2010 Elsevier B.V. All rights reserved.

Yahlali N.,Institute Fsica Corpuscular Centro Mixto UV CSIC | Irastorza I.G.,University of Zaragoza
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2011

The NEXT collaboration aims at building a 100 kg high-pressure Xenon gas TPC enriched in 136Xe isotope, to measure its two double-beta decay modes and to explore the degenerate hierarchy of the neutrino mass. The high-pressure Xenon gas offers the possibility to record the event energy with near-intrinsic resolution using electroluminescence, as well as the event track and topology patterns. These are the key features of a robust double-beta decay experiment which are presently being investigated in the first NEXT prototypes, the so-called NEXT0 and NEXT1. In this paper, the prototypes being developed at IFIC and University of Zaragoza are described and preliminary results are outlined. © 2010 Elsevier B.V. All rights reserved.

Jodra P.,University of Zaragoza
Mathematics and Computers in Simulation | Year: 2010

We provide procedures to generate random variables with Lindley distribution, and also with Poisson-Lindley or zero-truncated Poisson-Lindley distribution, as simple alternatives to the existing algorithms. Our procedures are based on the fact that the quantile functions of these probability distributions can be expressed in closed form in terms of the Lambert W function. As a consequence, the extreme order statistics from the above distributions can also be computer generated in a straightforward manner. © 2010 IMACS.

Wu Y.-T.,University of Cambridge | Fratiglioni L.,Karolinska Institutet | Matthews F.E.,Institute of Public Health | Matthews F.E.,Newcastle University | And 4 more authors.
The Lancet Neurology | Year: 2016

Dementia is receiving increasing attention from governments and politicians. Epidemiological research based on western European populations done 20 years ago provided key initial evidence for dementia policy making, but these estimates are now out of date because of changes in life expectancy, living conditions, and health profiles. To assess whether dementia occurrence has changed during the past 20-30 years, investigators of five different studies done in western Europe (Sweden [Stockholm and Gothenburg], the Netherlands [Rotterdam], the UK [England], and Spain [Zaragoza]) have compared dementia occurrence using consistent research methods between two timepoints in well-defined geographical areas. Findings from four of the five studies showed non-significant changes in overall dementia occurrence. The only significant reduction in overall prevalence was found in the study done in the UK, powered and designed explicitly from its outset to detect change across generations (decrease in prevalence of 22%; p=0·003). Findings from the study done in Zaragoza (Spain) showed a significant reduction in dementia prevalence in men (43%; p=0·0002). The studies estimating incidence done in Stockholm and Rotterdam reported non-significant reductions. Such reductions could be the outcomes from earlier population-level investments such as improved education and living conditions, and better prevention and treatment of vascular and chronic conditions. This evidence suggests that attention to optimum health early in life might benefit cognitive health late in life. Policy planning and future research should be balanced across primary (policies reducing risk and increasing cognitive reserve), secondary (early detection and screening), and tertiary (once dementia is present) prevention. Each has their place, but upstream primary prevention has the largest effect on reduction of later dementia occurrence and disability. © 2016 Elsevier Ltd.

Bernardi S.,University of Turin | Merseguer J.,University of Zaragoza | Petriu D.C.,Carleton University
Software and Systems Modeling | Year: 2011

The importance of assessing software non-functional properties (NFP) beside the functional ones is well accepted in the software engineering community. In particular, dependability is a NFP that should be assessed early in the software life-cycle by evaluating the system behaviour under different fault assumptions. Dependability-specific modeling and analysis techniques include for example Failure Mode and Effect Analysis for qualitative evaluation, stochastic Petri nets for quantitative evaluation, and fault trees for both forms of evaluation. Unified Modeling Language (UML) may be specialized for different domains by using the profile mechanism. For example, the MARTE profile extends UML with concepts for modeling and quantitative analysis of real-time and embedded systems (more specifically, for schedulability and performance analysis). This paper proposes to add to MARTE a profile for dependability analysis and modeling (DAM). A case study of an intrusion-tolerant message service will offer insight on how the MARTE-DAM profile can be used to derive a stochastic Petri net model for performance and dependability assessment. © 2009 Springer-Verlag.

Carus L.,University of Zaragoza
Accident Analysis and Prevention | Year: 2010

Very little research exists regarding the risks of visiting snow destinations. This study attempts to bridge this gap through insights into skiers' perceptions of risk, of great relevance to snow industry stakeholders, by identifying factors that influence skiers. The research was conducted in the Spanish Pyrenees, using information gathered from adult members of two ski clubs that regularly visit this snow destination. Skiing risks, accommodation risks and public safety risks were found to have the most important bearing on visitors' risk perceptions. However, actual figures demonstrate that respondents had some difficulties in assessing the typicality of the risk items and tended to misjudge the true level of the risks. © 2009 Elsevier Ltd. All rights reserved.

Here we report the climatic changes, deduced from the small-mammals assemblage evolution, during the Late Pleistocene (ca. 125-10 kyr) from three caves (Cova del Gegant, Cova de l'Arbreda, Cova Colomera) and a rock shelter (Abric Romaní) located in the Catalonian region (North-East Spain). We used the Mutual Climatic Range Principle method to obtain quantitative climatic data. This quantitative climatic data permit us to observe the temperature and precipitations variations during the greater part of the Late Pleistocene and compared it with the current climate in this region of the Iberian Peninsula.

Bryozoans are among the most abundant fossil groups in the cool water limestones that characterize the uppermost Katian (Upper Ordovician) of Southwestern Europe and North Africa. The Cystoid Limestone Formation, the representative unit of those widespread rocks in the Iberian Chains (NE Spain), yields one of the most diversified bryozoan faunas of the whole area. Herein the first systematic description of the trepostomate family Monticuliporidae is undertaken, this is one of the most diverse families within the associations collected. Four species of the genera Monticulipora and Prasopora are described, including the new species Monticulipora cystiphragmata n. sp. and Prasopora spjeldnaesi n. sp., and an indeterminate Monticuliporidae. Monticulipora and Prasopora have shown to be very similar genera, with several species that are difficult to distinguish between them. Their diagnoses include common features such as the wall microstructure, density of mesozoecia, and number of acanthostyles. Herein a new generic diagnosis of Monticulipora is proposed, putting special emphasis on the shape and distribution of cystiphragms. The species Monticulipora kolaluensis is identified for the first time out of Siberia. Although the record of these new taxa can indicate a certain isolation of the Iberian Chains region within the North Gondwana platform, the occurrence of Prasopora carnica shows a relation to the neighbouring Carnic Alps. © Publications Scientifiques du Muséum national d'Histoire naturelle, Paris.

Ollero A.,University of Zaragoza
Geomorphology | Year: 2010

The 346 km of the middle Ebro River between Logroño and La Zaida is a free meandering channel in a wide floodplain. This reach contains a discontinuous riparian corridor, including valuable riparian forests and oxbow lakes. The Ebro has witnessed substantial changes in channel morphology, gravel bars, riparian vegetation and floodplain uses over the last 80 years. The growth in sinuosity, migrations and meander cut-offs have been frequent before 1981. Afterwards, bank protections and dykes have stabilized the channel. There has been a progressive and significant decrease of both the area covered by water and the gravel bars without plant colonization. As a result the width of the riparian corridor has been dramatically reduced for human use. The deceleration and near elimination of the free meander dynamics of the Ebro channel represent an important loss of natural heritage. Dams, land-use changes throughout the basin, and construction of flood defences that restrict the main channel have changed the river system behaviour, which urgently needs a management plan combining both improvement and risk reduction. The solution proposed is the creation of a "Fluvial Territory". © 2009 Elsevier B.V. All rights reserved.

Fernandez-Olmos M.,University of Zaragoza
British Food Journal | Year: 2011

Purpose: The aim of this research is to determine how trust might moderate the effect of asset specificity on the contractual choice. Design/methodology/approach: The sample is drawn from the qualified appellation of origin (DOCa) Rioja wine market. A binomial logit was used as the primary technique for investigation of the hypothesis for the final sample size of 68 observations (34 oral contracts and 34 written contracts). Findings: The evidence presented in this paper points to the fact that asset specificity, the most important characteristic in transaction cost economics, will not be a strong predictor of the level of contract formalisation for transactions that enjoy a high level of trust. Research limitations/implications: This study has important limitations that imply caution in generalising the findings. First, the agrarian legal framework is likely to alter the effectiveness of formal contracts as governance devices. Another limitation of this analysis is that it is not a dynamic analysis and, hence, it does not consider the possibility of trust emerging over time. Practical implications: It is suggested that the possession of trust between contractual parties allows them to reduce transaction costs without resorting to a high level of contractual formalisation. Originality/value: This paper is useful for practitioners and academics in the field of contractual choice. The research provides some initial insight into the moderating influence of trust on the relationship between asset specificity and level of contractual incompleteness in the viticulture sector. © Emerald Group Publishing Limited.

Lacroix L.-M.,INSA Toulouse | Arenal R.,University of Zaragoza | Viau G.,INSA Toulouse
Journal of the American Chemical Society | Year: 2014

Ultrathin chemically grown gold nanowires undergo irremediable structural modification under external stimuli. Thanks to dynamic high-angle annular dark-field imaging, electron-beam-induced damage was followed, revealing the formation of linear chains of gold atoms as well as reactive clusters on the side, opening fascinating prospects for applications in both catalysis and electronic transport. © 2014 American Chemical Society.

New fossil discoveries in the middle Cambrian of Spain have considerably expanded our knowledge of the temporal and spatial distribution of some major clades of echinoderms including sucocystid cinctans, isorophid edrioasteroids, cothurnocystid stylophorans, ctenocystoids, and a new group of blastozoans ("eocystitids"). Because many of these taxa appear close to the beginning of the middle Cambrian, it seems likely that their origins must be placed in the early Cambrian. These results, based on articulated specimens provided from Echinoderm Lagerstätten, agree with the hidden diversity provided from isolated ossicles from other Gondwanan areas. © 2010 Geological Society of America.

Gutierrez M.,University of Zaragoza
Zeitschrift fur Geomorphologie | Year: 2010

This study provides chronological evidence of the influence of climatic variability in the generation of late Quaternary talus flatiron sequences in Spain. The temporal clustering of the OSL and radiocarbon dates obtained from talus flatiron deposits indicates that warm/wet and cold/dry periods controlled the accumulation and incision processes in the slopes, respectively, that led to the development of talus flatirons. These results strongly suggest that talus flatiron sequences constitute valuable paleoclimatic records. Additional and more accurate geochronological data from Spain and other regions of the world would improve the potential of these poorly-known landforms in paleoenvironmental studies. © 2010 Gebr. Borntraeger Verlagsbuchhandlung, Stuttgart, Germany.

Arenas C.,University of Zaragoza | Pomar L.,University of the Balearic Islands
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2010

The Santanyí Limestone, a 30-35-m thick upper Miocene limestone succession cropping out in Mallorca, contains abundant microbialite deposits, the shape, microstructure and texture of which was controlled by environmental factors: depth, energy and salinity. Three main types of microbialites are distinguished: (1) domed (DNOS) and stratiform, mostly undulate (UNOS) non-oolitic stromatolites, (2) undulate oolitic laminites (UOL) and (3) domed-oolitic thrombolites (DOTs). Based on lithofacies associations and occurrence of microbialite types, the Santanyí Limestone succession is subdivided into five stratigraphic units (I to V) separated by sharp surfaces. Within units II, III and V, the vertical evolution of microbialites was induced by changes in accommodation space/depth: (1) intertidal/very-shallow subtidal conditions at the base were induced by flooding over a wide area, (2) continued sea-level rise caused submergence to subtidal conditions, and (3) a significant bathymetric decrease created the sharp surface bounding these units.In units II and III, NOS accumulated in variable energy and depth conditions, as buildups with thick, somewhat discontinuous and mostly non-isopachous lamination, surrounded by oolitic grainstones with wave and current structures and oolitic intraclasts. In contrast, thin and generally regular and smooth lamination of NOS in unit V suggests, along with the absence of oolite grainstones and macrobiota, calm and restricted, maybe more saline, conditions.UOL, consisting of oolitic layers separated by thin micritic laminae, developed adjacent to NOS in units II and III and to DOT at the lower part of unit III, in shallow-water and low-energy conditions. Both ooids and micrite laminae have evidence for biogenesis. Micritized ooids containing microbial remains are common. Micritic laminae in UOL and the dark micritic laminae in NOS are thought to represent bacterially enhanced calcite precipitation and lithification during periods of low sedimentation.Oolitic thrombolites containing macrobiota are only present in unit III. They represent deeper and open-marine conditions affected by high-energy events, in which microbially mediated precipitation favoured microbialite accretion and lithification. © 2010 Elsevier B.V.

Christensen J.,Autonomous University of Madrid | Christensen J.,CSIC - Institute of Optics | Martin-Moreno L.,University of Zaragoza | Garcia-Vidal F.J.,Autonomous University of Madrid
Applied Physics Letters | Year: 2010

In this paper we design an acoustic metamaterial for broadband sound blockage that is easy to fabricate and presents tunable capabilities. Two adjacent holey plates are predicted to support a gap mode which is responsible of a forbidden band, displaying a negative effective bulk modulus. This acoustic metamaterial exhibits a weak dispersion with parallel momentum implying that strong attenuation appears for a broad range of angles of incident sound. Its bandwidth can be tailored at will by varying the separation between the two holey plates. © 2010 American Institute of Physics.

Garcia-Marco F.-J.,University of Zaragoza
Electronic Library | Year: 2011

Purpose - This paper sets out to address the issue of the impact and evolution of digital libraries and information services using the concept of information ecologies. Design/methodology/approach - After setting the perspective, digital libraries are explored from their functional logic inside the social subsystem that deals with transferring knowledge in the form of information among people and generations. The current landscape is then presented, which is complicated by the enormous technological shift in course. The concept of information ecology is useful for reducing this complexity. Findings - Trends affecting modern information ecology in which digital libraries are evolving are studied. Specifically, eight noteworthy processes in this development are analyzed: ubiquity of information management; digital convergence; technological standardization and leverage; the surging of a worldwide space of collaboration, and competition; swift advances in the international division of informational work; the transformation of the physical information units toward the provision of proximity services; the entry of new agents in the field; and the growing emphasis on data management. Originality/value - The changing environment in the libraries field is explored using the concept of information ecologies. Some of the most important trends in the digital environment are identified and their effect on the social and economical functions of libraries is shown. Information ecology is very complex, with many actors, and libraries have some niches ensured (heritage preservation, proximity services ⋯), though others could be better performed by emerging full-digital organizations. © Emerald Group Publishing Limited.

Mur-Duenas P.,University of Zaragoza
Journal of Pragmatics | Year: 2011

In the last few decades the interpersonal nature of academic communication has been stressed in English for Academic Purposes literature. Taking metadiscourse as the analytical framework, this paper focuses on the cross-cultural analysis of interpersonally driven features in research article writing in a single discipline, Business Management. It aims at analysing to what extent the different contexts (i.e. the US international and the Spanish national) influence the strategic use of metadiscourse features in this discipline. The analysis is based on a corpus of 24 research articles from this discipline: 12 of them written in English by scholars based at North-American institutions and published in international journals, and another 12 written in Spanish by Spanish scholars and published in national journals. Significant differences are reported on the overall frequency of metadiscourse features as well as on the particular incidence of some categories in the two sub-corpora. The particular linguistic/cultural contexts of publication seem to influence scholars' rhetorical choices when writing their research articles. New knowledge appears to be interpersonally negotiated in different terms in research articles in the two cultural contexts within this disciplinary domain. © 2011 Elsevier B.V.

Garcia-Marco F.-J.,University of Zaragoza
Profesional de la Informacion | Year: 2011

The information pyramid, or DIKW hierarchy, is a key construct in information science and other related disciplines. Its concept, history and criticism are presented. Thereafter, the pyramid is enriched with the contributions of cognitive sciences in the last decades, and an enlarged model is proposed. Finally, a discussion of the different levels of the pyramid is presented from the point of view of the architecture of the human information system: data, information, knowledge and wisdom. As a result of very different points of view, the model is full of ambiguities and alternative interpretations, but nevertheless remains a fertile metaphor and a point of reference for the intra-disciplinary and trans-disciplinary dialog at the maximum level of abstraction.

Lanas A.,University of Zaragoza | Tornero J.,Hospital General Universitario Of Guadalajara | Zamorano J.L.,Servicio de Cardiologia
Annals of the Rheumatic Diseases | Year: 2010

Background: Medical management of adults with osteoarthritis (OA) who require non-steroidal antiinfl ammatory drugs (NSAIDs) must be decided after assessing prevalent gastrointestinal (GI) and cardiovascular (CV) risks in the individual patient. Objective: To evaluate the GI and CV risk profile of patients with OA who require NSAIDs. Methods: A transversal, multicentre and observational study was conducted in consecutive patients with OA who were considered candidates for NSAID treatment and were visited by 374 unselected rheumatologists throughout the National Health System. Patients were classified into three risk groups (low, moderate and high) for their GI and CV characteristics. These were defined by considering the presence of a number of well-established GI risk factors or by application of the Systematic Coronary Risk Evaluation model for assessing the overall risk for CV disease, respectively. Results: Of 3293 consecutive patients, most (86.6%) were at increased GI risk and a considerable number, 22.3%, were at high GI risk. The CV risk was high in 44.2% of patients, moderate in 28.5% and low in 27.3%. Overall, 15.5% of patients presented a very high-risk profile, having high GI and CV risks. The type of NSAID prescription was similar regardless of the associated GI and CV risk profile. Conclusion: Most patients with OA requiring NSAIDs for pain control showed a high prevalence of GI and CV risk factors. Over half of the patients were at either high GI or CV risk, or both, such that the prescription of OA treatments should be very carefully considered.

Following the trends observed for the last 2-3 years, the most significant and recent advances in the area of gastrointestinal lesions associated with anti-inflammatory drugs (NSAIDs) have focused on adverse effects in the distal intestine and on issues related to the toxicity associated with antiplatelet therapy. New data reinforce evidence that NSAIDs and antiplatelet therapy are associated with an increased risk of serious complications in both the upper and lower gastrointestinal tract, opening up several lines of research in prevention and therapy based on probiotics, antibiotics and mucosal protectants. The interaction between Helicobacter pylori infection and NSAIDs or aspirin remains controversial but a positive interaction between this bacterium and NSAIDs seems to be reinforced. Several systematic reviews confirm that the combination of gastrotoxic drugs significantly increases the risk of gastrointestinal bleeding, which should reinforce existing prevention strategies, and that new anticoagulant agents do not appear to reduce the risk of gastrointestinal bleeding. Once gastrointestinal hemorrhage has occurred, several studies have indicated the need to implement simpler prognostic scales than those used today. Notable innovations are the development of a disposable endoscope for acute upper gastrointestinal bleeding events and a promising new hemostatic technique, hemospray, applied locally over the bleeding lesion. © 2012 Elsevier España, S.L.

Colmenar J.,University of Zaragoza
Acta Palaeontologica Polonica | Year: 2016

The study of the strophomenide brachiopods of the subfamily Rafinesquininae present in the main Upper Ordovician sections, representing the Mediterranean margin of Gondwana, has revealed an increase in diversity of the group at the region during that time. The studied collections are from the Moroccan Anti-Atlas, the Iberian and the Armorican massifs, the Iberian Chains, Pyrenees, Montagne Noire, Sardinia, and Bohemia. Two genera of the subfamily Rafinesquininae have been recorded. Of them, the cosmopolitan Rafinesquina is the only one previously reported from the region and Kjaerina is found for the first time outside Avalonia, Baltica, and Laurentia. Additionally, two new subgenera have been described, Kjaerina (Villasina) and Rafinesquina (Mesogeina). Furthermore, the new species Rafinesquina (Mesogeina) gabianensis, Rafinesquina (Mesogeina) loredensis, Kjaerina (Kjaerina) gondwanensis, Kjaerina (Villasina) pedronaensis, Kjaerina (Villasina) pyrenaica, and Kjaerina (Villasina) meloui have been described. In addition, other species of these genera previously known from isolated localities in the region, such as Rafinesquina pseudoloricata, Rafinesquina pomoides, and Hedstroemina almadenensis are revised and their geographic range expanded. The adaptive radiation experienced by the rafinesquinines at the Mediterranean region during middle to late Katian, was probably related to changes in the regime of sedimentation and water temperature caused by the global warming Boda event. © 2016 J. Colmenar.

Ayora-Canada M.J.,University of Jaen | Dominguez-Arranz A.,University of Zaragoza | Dominguez-Vidal A.,University of Jaen
Journal of Raman Spectroscopy | Year: 2012

Raman microspectroscopy has been employed for the characterization of 16 samples of ancient Iberian pottery. These sherds of vessels were found in the archaeological site of La Vispesa in Tamarite de Litera (Huesca, Spain) and correspond to the Iberian time. The composition of certain mineral phases such as non-plastic inclusions has been particularly considered with a view to obtaining information on the source materials and their provenance, as well as the technological conditions of ceramic production. Typical minerals such as calcite and quartz were found in most of the samples. The presence of anatase in a group of the samples suggested the use of different clays in the production of the vessels. Furthermore, the absence of rutile in these samples, together with the identification of calcite, is indicative of a mild firing temperature. Hematite was identified in all samples, both in the ceramic body and in the decoration. Differences in the position of the bands and relative intensities characterized hematite in terms of crystallinity and origin. An attempt to assign the samples to different production centers was made according to their chemical composition and morphology. Copyright © 2011 John Wiley & Sons, Ltd.

Gomez J.B.,University of Zaragoza
Energy | Year: 2011

We propose a model for an exhausted upper continental crust. The Crepuscular Earth represents a degraded planet where all resources have been extracted and dispersed, and all fossil fuels have been burned. The starting point of the model of crepuscular crust is the composition given by the geochemist Grigor'ev, which is constrained by the conservation of mass statement between the chemical composition of the crust in terms of elements and in terms of minerals. Additionally, the model is given geological consistence, by introducing a series of assumptions based on geological observations. As a result, the obtained crepuscular crust is composed of the 294 most abundant minerals. Together with the model of exhausted atmosphere and hydrosphere developed in a previous paper, the study will serve as a reference for calculating the exergy of the current mineral capital on Earth and its degradation velocity. © 2010 Elsevier Ltd.

Evangelisti M.,University of Zaragoza | Brechin E.K.,University of Edinburgh
Dalton Transactions | Year: 2010

Molecular nanomagnets are considered valid candidates for magnetic refrigeration at low temperatures. Designing these materials for enhanced cooling requires the control and optimization of the quantum properties at the molecular level, in particular: spin ground state, magnetic anisotropy, and presence of low-lying excited spin states. Herein, we present the theoretical framework together with a critical review of recent results, and perspectives for future developments. © The Royal Society of Chemistry 2010.

Zamora S.,University of Zaragoza | Smith A.B.,Natural History Museum in London
Acta Palaeontologica Polonica | Year: 2010

Two new middle Cambrian edrioasteroid (Echinodermata), Protorophus hispanicus gen. et sp. nov., and Isorophida gen. et sp. indet., are described from the early middle Cambrian (Cambrian Series 3, Stage 5) of Spain. These are the oldest and probably the most primitive isorophids, a clade previously known from the upper Cambrian onwards. Specimens are attached to trilobite fragments indicating that edrioasteroids had by this time separated into two lineages each with different strategies for attachment, sediment attachers and hard substrate attachers. The single U-shaped ambulacral flooring plates of Protorophus are unique while Isorophida gen. et sp. indet. shares the presence of spines in common with some pyrgocystitid isorophids. The shift from facultative soft-bottom attachment to obligate hard-ground attachment in edrioasteroids involved the retention of a juvenile trait into adulthood and was already underway by the middle Cambrian.

Gil J.J.,University of Zaragoza | San Jose I.,Instituto Aragones Of Estadistica Camino Of Las Torres 53
Optics Communications | Year: 2010

From our previous definition of the indices of polarimetric purity for 3D light beams [J.J. Gil, J.M. Correas, P.A. Melero and C. Ferreira, Monogr. Semin. Mat. G. de Galdeano 31, 161 (2004)], an analysis of their geometric and physical interpretation is presented. It is found that, in agreement with previous results, the first parameter is a measure of the degree of polarization, whereas the second parameter (called the degree of directionality) is a measure of the mean angular aperture of the direction of propagation of the corresponding light beam. This pair of invariant, non-dimensional, indices of polarimetric purity contains complete information about the polarimetric purity of a light beam. The overall degree of polarimetric purity is obtained as a weighted quadratic average of the degree of polarization and the degree of directionality. © 2010 Elsevier B.V. All rights reserved.

One way of producing nearly CO 2 free electricity is by using biomass as a combustible. In many cases, removal of CO 2 in biomass grown is almost the same as the emissions for the bioelectricity production at the power plant. For this reason, bioelectricity is generally considered CO 2 neutral. For large-scale biomass electricity generation two alternatives can be considered: biomass-only fired power plants, or cofiring in an existing coal power plant. Among other factors, two important aspects should be analyzed in order to choose between the two options. Firstly, which is the most appealing alternative if their Greenhouse Gases (GHG) Emissions savings are taken into account. Secondly, which biomass resource is the best, if the highest impact reduction is sought. In order to quantify all the GHG emissions related to each system, a Life Cycle Assessment (LCA) methodology has been performed and all the processes involved in each alternative have been assessed in a cradle-to-grave manner. Sensitivity analyses of the most dominant parameters affecting GHG emissions, and comparisons between the obtained results, have also been carried out. © 2010 Elsevier Ltd.

Zheng Y.-Z.,University of Manchester | Evangelisti M.,University of Zaragoza | Winpenny R.E.P.,University of Manchester
Chemical Science | Year: 2011

Three 3d-4f phosphonate complexes, [CoII 8GdIII 8(μ3-OH)4(NO3)4(O3PtBu)8(O2CtBu)16], [CoII 8GdIII 4(O3PtBu)6(O2CtBu)16] and [CoII 4GdIII 6(O3PCH2Ph)6(O2CtBu)14(MeCN)2], have been synthesized and have structures that can be related to molecular grids. Magnetic studies show they have promise as low temperature magnetic refrigerants. © The Royal Society of Chemistry 2011.

Rubinstein M.,Massachusetts Institute of Technology | Gutierrez D.,University of Zaragoza | Sorkine O.,New York University | Shamir A.,The Interdisciplinary Center
ACM Transactions on Graphics | Year: 2010

The numerous works on media retargeting call for a methodological approach for evaluating retargeting results. We present the first comprehensive perceptual study and analysis of image retargeting. First, we create a benchmark of images and conduct a large scale user study to compare a representative number of state-of-the-art retargeting methods. Second, we present analysis of the users' responses, where we find that humans in general agree on the evaluation of the results and show that some retargeting methods are consistently more favorable than others. Third, we examine whether computational image distance metrics can predict human retargeting perception. We show that current measures used in this context are not necessarily consistent with human rankings, and demonstrate that better results can be achieved using image features that were not previously considered for this task. We also reveal specific qualities in retargeted media that are more important for viewers. The importance of our work lies in promoting better measures to assess and guide retargeting algorithms in the future. The full benchmark we collected, including all images, retargeted results, and the collected user data, are available to the research community for further investigation at http://people.csail.mit.edu/ mrub/retargetme. © 2010 ACM.

Garcia-Magarino I.,University of Zaragoza
Expert Systems with Applications | Year: 2015

There are plenty of expert and intelligent systems related to tourism, either for (1) selecting appropriate paths, (2) recommending routes or travel packages, (3) simulating certain implications in tourism, or (4) virtually immersing tourists. However, to the best of author's knowledge, none of these works provides a system that simulates how many tourist people sign up for each tourist route considering the features of some routes and tourists. This article presents an Agent-based Simulator (ABS) that covers this gap of the literature and is called Agent-based Simulator for Tourist Urban Routes (ABSTUR). It receives input from a set of routes and certain number of tourists with different types, and provides the number of tourist people signed up for each route after the simulation. ABSTUR has been experienced by assisting a group of tourism experts in designing a set of tourist routes in the historic center of Madrid. In this manner, experts were able to avoid collections of routes with overcrowded or non-profitable routes. ABSTUR has also proven to be efficient by comparing it with another ABS with the same specifications. © 2015 Elsevier Ltd. All rights reserved.

Gonzalez A.,University of Zaragoza
Mathematical Geosciences | Year: 2010

The area of a spherical region can be easily measured by considering which sampling points of a lattice are located inside or outside the region. This point-counting technique is frequently used for measuring the Earth coverage of satellite constellations, employing a latitude-longitude lattice. This paper analyzes the numerical errors of such measurements, and shows that they could be greatly reduced if the Fibonacci lattice were used instead. The latter is a mathematical idealization of natural patterns with optimal packing, where the area represented by each point is almost identical. Using the Fibonacci lattice would reduce the root mean squared error by at least 40%. If, as is commonly the case, around a million lattice points are used, the maximum error would be an order of magnitude smaller. © 2009 International Association for Mathematical Geosciences.

Zheng Y.-Z.,University of Manchester | Zheng Y.-Z.,Xian University of Science and Technology | Evangelisti M.,University of Zaragoza | Tuna F.,University of Manchester | Winpenny R.E.P.,University of Manchester
Journal of the American Chemical Society | Year: 2012

The synthesis, structures, and magnetic properties of six families of cobalt-lanthanide mixed-metal phosphonate complexes are reported in this Article. These six families can be divided into two structural types: grids, where the metal centers lie in a single plane, and cages. The grids include [4 × 3] {Co 8Ln 4}, [3 × 3] {Co 4Ln 6}, and [2 × 2] {Co 4Ln 2} families and a [4 × 4] {Co 8Ln 8} family where the central 2 × 2 square is rotated with respect to the external square. The cages include {Co 6Ln 8} and {Co 8Ln 2} families. Magnetic studies have been performed for these compounds, and for each family, the maximum magnetocaloric effect (MCE) has been observed for the Ln = Gd derivative, with a smaller MCE for the compounds containing magnetically anisotropic 4f-ions. The resulting entropy changes of the gadolinium derivatives are (for 3 K and 7 T) 11.8 J kg -1 K -1 for {Co 8Gd 2}; 20.0 J kg -1 K -1 for {Co 4Gd 2}; 21.1 J kg -1 K -1 for {Co 8Gd 4}; 21.4 J kg -1 K -1 for {Co 8Gd 8}; 23.6 J kg -1 K -1 for {Co 4Gd 6}; and 28.6 J kg -1 K -1 for {Co 6Gd 8}, from which we can see these values are proportional to the percentage of the gadolinium in the core. © 2011 American Chemical Society.

Martin-Vide J.P.,University of Barcelona | Ferrer-Boix C.,University of Barcelona | Ollero A.,University of Zaragoza
Geomorphology | Year: 2010

Historical information on river degradation was used in a case study on the Gállego River, a tributary of the Ebro River, in northeastern Spain. The Gállego drains about 4000 km2 of the southern slopes of the Pyrenees. Good channel surveys since the 1940s allowed a comparison of longitudinal bed profiles over time. Over this period about 1 million m3 of gravel was mined according to the archival records. The volume of alluvium lost due to incision in the same period was 2 million m3. This imbalance is tentatively explained by a budget model based on a bedload equation and an algorithm to determine whether the effective bedload transport is controlled by the transport capacity or by the supply of sediment. It appears that the incision process has changed the magnitude of the shear stresses on channel bed. As the river became deeper, the channel could accommodate higher discharges without overbank flooding. The results obtained from a second model based on diffusion equation for the bed elevation compared well with the field data. This model is based on the hypotheses of steady uniform flow regarding water and sediment conservation. © 2009 Elsevier B.V. All rights reserved.

Adell J.A.,University of Zaragoza
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences | Year: 2012

We approximate each generalized Stieltjes constant γ n(a) by means of a finite sum involving Bernoulli numbers. Such an approximation has a quasi-geometric rate of convergence, which improves as Re(a) increases. A more detailed analysis, including numerical computations, is carried out for the constants γ0(1) and γ1(1). The key point in the proof is a probabilistic representation of the aforementioned constants, obtained as a consequence of a differential calculus concerning the gamma process. © 2011 The Royal Society.

Gil J.J.,University of Zaragoza
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2014

The depolarizing properties of a generic Mueller matrix are synthesized from a corresponding nondepolarizing reference Mueller matrix, which is appropriately factorized and transformed by sequentially adjusting the values of three indices of polarimetric purity (IPP) [Opt. Commun. 284, 38 (2011)]. This procedure allows generating type-I and type-II arbitrary Mueller matrices from an adequate choice of the reference Mueller matrix and, by reducing, in a consistent way, the starting 1-valued IPP. This synthesis procedure also provides better understanding of the sources and structure of depolarization. © 2014 Optical Society of America.

Langley S.K.,Monash University | Chilton N.F.,Monash University | Moubaraki B.,Monash University | Hooper T.,University of Edinburgh | And 3 more authors.
Chemical Science | Year: 2011

The use of triethanolamine (teaH3) in 3d/4f chemistry produces the enneanuclear cluster compound [CuII 5GdIII 4O2(OMe)4(teaH)4(O2CC(CH3)3)2(NO3)4]·2MeOH·2Et2O (1·2MeOH·2Et2O) whose molecular structure comprises a series of vertex- and face-sharing {GdIIICuII 3} tetrahedra. Magnetic studies reveal a large number of spin states populated even at the lowest temperatures investigated. Combined with the high magnetic isotropy, this enables 1 to be an excellent magnetic refrigerant for low temperature applications. © The Royal Society of Chemistry 2011.

Vellisca M.Y.,University of Zaragoza | Latorre J.I.,Obispo Polanco Hospital
Rheumatology International | Year: 2014

Our aim was to assess the effect of dietary elimination of monosodium glutamate (MSG) and aspartame on perceived pain in fibromyalgia. A total of 72 female patients with fibromyalgia were randomized to discontinuation of dietary MSG and aspartame (n = 36) or waiting list (n = 36). Patients were requested to rate their pain using a seven-point scale. Comparisons between both groups showed no significant differences on pain referred during the baseline or after the elimination of dietary MSG and aspartame. The discontinuation of dietary MSG and aspartame did not improve the symptoms of fibromyalgia. © 2013 Springer-Verlag.

Perez-Lopez F.R.,University of Zaragoza | Hita-Contreras F.,University of Jaen
Climacteric | Year: 2014

Pelvic pain is a frequent complaint in women during both reproductive and post-reproductive years. Vulvodynia includes different manifestations of chronic vulvar pain with no known cause. Many women do not receive a diagnosis and appropriate treatment. Pudendal neuralgia is a painful condition caused by inflammation, compression or entrapment of the pudendal nerve; it may be related to or be secondary to childbirth, pelvic surgery, intense cycling, sacroiliac skeletal abnormalities or age-related changes. Clinical characteristics include pelvic pain with sitting which increases throughout the day and decreases with standing or lying down, sexual dysfunction and difficult with urination and/or defecation. To confirm pudendal neuralgia, the Nantes criteria are recommended. Treatment includes behavioral modifications, physiotherapy, analgesics and nerve block, surgical pudendal nerve decompression, radiofrequency and spinal cord stimulation. © 2014 International Menopause Society.

Introduction. One of the primary needs of human beings is setting emotional bonds perceived as unconditional and everlasting. In the first moment of life, if development is harmonious, this need is satisfied by the care and attention received from the mother. Several studies have demonstrated how importance it is for the emotional development of the child and of the species in general. Aim. To review the main knowledge provided by several current researches on neurobiological changes that occurs in the mother to ensure the optimal development of the offspring. Development. Data from different sources show that even during pregnancy, childbirth and the very first mother-child interactions, structural, functional and neuroendocrine changes are noticed at the maternal brain which predispose the mother for her baby's care and attention. These maternal brain changes affect the infant brain, and therefore, the development as much in the childhood years as later. Furthermore, the effects of these early mother-child interactions on brain and child development are even transgenerational. Conclusions. Despite these important results which show maternal brain plasticity and the relevance of their social, educational and health implications, there is still a long way to go in order to understand the processes in the maternal brain and its influence on the child development. Interdisciplinary labor is required to answer these questions and consequently, to improve human development. © 2013 Revista de Neurología.

Fuertes S.,University of Bath | Woodall C.H.,University of Bath | Raithby P.R.,University of Bath | Sicilia V.,University of Zaragoza
Organometallics | Year: 2012

The mononuclear complex [(EtO 2C-C ^N ^C)Pt(dmpyz)] (1) (dmpyz = 2,5-dimethylpyrazine) has been synthesized by reaction of [(EtO 2C-C ^N ^C)Pt(dmso)] (A) with dmpyz in a 1:1 molar ratio in dichloromethane. Complex 1 is the precursor for preparing the homodinuclear complex [{(EtO 2C-C ^N ^C)Pt} 2(μ-dmpyz)] (2) and the heterotrinuclear clusters [{(EtO 2C-C ^N ^C)Pt(dmpyz)} 2M]X (M = Cu, X = PF 6 (3); M = Ag, X = BF 4 (4)). Compounds 1, 2, and 4 were studied by X-ray diffraction methods. In the crystal packing of 1 and 2, the molecules display short intermolecular π•••π contacts, which control the solid-state emissive behavior. X-ray study on 4 shows two [Pt 2Ag] sandwich-type clusters in the asymmetric unit, both with the two square-planar "(R-CNC)Pt(dmpyz)" moieties stabilized by two Pt → Ag donor-acceptor bonds as well as by η 1- and η 2-Ag-C interactions. Intramolecular π-π contacts were found between the pyridine rings of the CNC ligands within the same Pt 2Ag cluster. 1H and 195Pt NMR studies confirm that the Pt 2M cluster is also retained in solution at room temperature. 195Pt NMR spectra of 3 and 4 show signals shifted significantly downfield when comparing with that for the monomer (1), which is attributed to the presence of Pt-M dative bonds. At lower temperatures (T = 193 K), the copper derivative definitely falls apart, whereas the silver one still holds up unbroken. In the solid state at 77 K, compounds 1-4 give red emissions arising from 3ππ excited states due to the intra- or intermolecular π-π contacts observed in the crystal structures. As expected, in glassy solutions (77 K), compound 3 displays analogous emissions to those from the starting material (1). Complexes 1 and 2 show structured emission bands that are particularly sensitive to the λ ex (HE and LE). In contrast, 4 displays an unstructured emission at 680 nm with a shoulder at 556 nm; both are not dependent on the λ ex. DFT and TDDFT computational studies have been performed on 1 and 2, which support the conclusions drawn from the photophysical studies. © 2012 American Chemical Society.

Gil-Extremera B.,University of Granada | Cia-Gomez P.,University of Zaragoza
International Journal of Hypertension | Year: 2012

Background. The incidence of hypertension in the Western countries is continuously increasing in the elderly population and remains the leading cause of cardiovascular and morbidity. Methods. we analysed some significant clinical trials in order to present the relevant findings on those hypertensive population. Results. Several studies (SYST-EUR, HYVET, CONVINCE, VALUE, etc.) have demonstrated the benefits of treatment (nitrendipine, hydrochrotiazyde, perindopril, indapamide, verapamil, or valsartan) in aged hypertensive patients not only concerning blood pressure values but also the other important risk factors. Conclusion. Hypertension is the most prevalent cardiovascular disorder in the Western countries, and the relevance of receiving pharmacological treatment of hypertension in aged patients is crucial; in addition, the results suggest that combination therapynitrendipine plus enalaprilcould have more benefits than those observed with the use of nitrendipine alone. © 2012 Blas Gil-Extremera and Pedro Cía-Gómez.

Mancuso R.,Autonomous University of Barcelona | Santos-Nogueira E.,Autonomous University of Barcelona | Osta R.,University of Zaragoza | Navarro X.,Autonomous University of Barcelona
Clinical Neurophysiology | Year: 2011

Objective: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by loss of motoneurons of the primary motor cortex, the brainstem and the spinal cord, for which there are not effective treatments. Several transgenic mice that mimic motoneuron disease have been used to investigate potential treatments. The objective of this work is to characterize electrophysiologically the SOD1G93A transgenic mouse model of ALS, and to provide useful markers to improve early detection and monitoring of progression of the disease. Methods: We performed nerve conduction tests, motor unit number estimation (MUNE), H reflex tests and motor evoked potentials (MEPs) in a cohort of transgenic and wild type mice from 4 to 16. weeks of age. Results: The results revealed dysfunction of spinal motoneurons evidenced by deficits in motor nerve conduction tests starting at 8. weeks of age, earlier in proximal than in distal muscles of the hindlimb. MUNE demonstrated that spinal motoneurons loss muscle innervation and have a deficit in their sprouting capacity. Motor evoked potentials revealed that, coexisting with peripheral deficits, there was a dysfunction of central motor tracts that started also at 8. weeks, indicating progressive dysfunction of upper motoneurons. Conclusions: These electrophysiological results provide important information about the SOD1G93A mouse model, as they demonstrate by the first time alterations of central motor pathways simultaneously to lower motoneuron dysfunction, well before functional abnormalities appear (by 12weeks of age). Significance: The finding of concomitant dysfunction of upper and lower motoneurons contributes to the validation of the SOD1G93A mouse as model of ALS, because this parallel involvement is a diagnostic condition for ALS. Electrophysiological tests can be used as early markers of the disease and to evaluate the potential benefits of new treatments on both upper and lower motoneurons. © 2011 International Federation of Clinical Neurophysiology.

Fernandez-Marin A.A.,Autonomous University of Puebla | Mendez-Bermudez J.A.,Autonomous University of Puebla | Carbonell J.,Polytechnic University of Valencia | Cervera F.,Polytechnic University of Valencia | And 2 more authors.
Physical Review Letters | Year: 2014

Experimental evidence demonstrating that anomalous localization of waves can be induced in a controllable manner is reported. A microwave waveguide with dielectric slabs randomly placed is used to confirm the presence of anomalous localization. If the random spacing between slabs follows a distribution with a power-law tail (Lévy-type distribution), unconventional properties in the microwave-transmission fluctuations take place revealing the presence of anomalous localization. We study both theoretically and experimentally the complete distribution of the transmission through random waveguides characterized by α=1/2 ("Lévy waveguides") and α=3/4, α being the exponent of the power-law tail of the Lévy-type distribution. As we show, the transmission distributions are determined by only two parameters, both of them experimentally accessible. Effects of anomalous localization on the transmission are compared with those from the standard Anderson localization. © 2014 American Physical Society.

Background/Objectives:The objective of the study is to describe the hydration status and to assess the main food- and/or fluid intake-associated factors in healthy adolescents.Subjects/Methods:A total of 194 adolescents from the city of Zaragoza aged 12.5–17.5 years (99 males) participating in the 'Healthy Lifestyle in Europe by Nutrition in Adolescence' (HELENA) cross-sectional study were included. First morning urine was collected, and osmolality was determined by freezing point depression osmometer. A self-reported computer-based 24-h dietary recall was applied the same day of the urine collection. Analysis of variance, Kruskal–Wallis procedure or Pearson’s χ2 analyses was used to examine the group associations.Results:Seventy-one percent of adolescents did not meet the European Food Safety Agency (EFSA) recommendations for average total water intake (TWI), and 68% had high first morning urine osmolality values. TWI and the proportion of those meeting EFSA reference values significantly (P<0.05) decreased with increased osmolality. Males who met the EFSA recommendations consumed significantly (P<0.05) more plain water (1035.13 vs 582.68 ml) and dairy drinks (368.13 vs 226.68 ml) than those who did not. In females, the consumption of water (1359.41 vs 620.44 ml) and sugar-sweetened beverages (214.61 vs 127.42 ml) was significantly higher in those meeting the EFSA recommendations than in those who did not. First morning urine osmolality was associated with vegetables (unstandardized β: −0.6; 95% confidence interval (CI): −1.02 and −0.18) and fruits intake (β: −0.41; 95% CI: −0.63 and −0.19) in males and with dairy drinks (β: −0.39; 95% CI: −0.76 and −0.02) and fruits (β: −0.41; 95% CI: −0.73 and −0.10) in females.Conclusions:There was a high prevalence of inadequate TWI and high urine osmolality among these Spanish adolescents. Lower urine osmolality was associated with higher consumption of vegetables in males, dairy drinks in females and fruits in both males and females.European Journal of Clinical Nutrition advance online publication, 16 December 2015; doi:10.1038/ejcn.2015.203. © 2015 Macmillan Publishers Limited

Gonzalez-Tudela A.,Autonomous University of Madrid | Huidobro P.A.,Autonomous University of Madrid | Martin-Moreno L.,University of Zaragoza | Tejedor C.,Autonomous University of Madrid | Garcia-Vidal F.J.,Autonomous University of Madrid
Physical Review Letters | Year: 2013

Here we present the theoretical foundation of the strong coupling phenomenon between quantum emitters and propagating surface plasmons observed in two-dimensional metal surfaces. For that purpose, we develop a quantum framework that accounts for the coherent coupling between emitters and surface plasmons and incorporates the presence of dissipation and dephasing. Our formalism is able to reveal the key physical mechanisms that explain the reported phenomenology and also determine the physical parameters that optimize the strong coupling. A discussion regarding the classical or quantum nature of this phenomenon is also presented. © 2013 American Physical Society.

Lippert B.,TU Dortmund | Sanz Miguel P.J.,TU Dortmund | Sanz Miguel P.J.,University of Zaragoza
Chemical Society Reviews | Year: 2011

Reports on spontaneous self-assembly processes between metal fragments and organic ligands frequently tend to ignore the fact that the product isolated and structurally characterized in most cases is only one out of a more or less large series of feasible ones. This is true even for rings containing as few as three or four metal ions. Here we shall review metallatriangles and metallasquares containing predominantly cis-square-planar metal entities and a range of bidentate bridging ligands. The most significant features contributing to the number of possible stereoisomers appear to be ligand symmetry and flexibility, viz. rotation of two halves of a ligand about a single bond, or rotation of the whole ligand about the metal-donor atom bonds. With low-symmetry bidentate ligands the number of isomers increases dramatically with ring size as a consequence of an increase in possible connectivity patterns, hence linkage isomers, and an increase in possible rotamer states of the bridging ligands. In this tutorial review it is demonstrated how complexity increases as the symmetry of the bridging ligands is lowered from D∞h and D 2h to C∞v, C2v, C2h and C s. Special attention will be paid to cyclic tri- and tetranuclear complexes of substituted pyrimidine ligands (C2v and Cs symmetries) as well as the flexible 2,2′-bipyrazine, which can adopt states of either C2v or C2h symmetry. Uses of these complexes and ways to reduce the number of isomers will be pointed out. © 2011 The Royal Society of Chemistry.

Rizzoli R.,University of Geneva | Bianchi M.L.,Bone Metabolism Unit | Garabedian M.,French Institute of Health and Medical Research | McKay H.A.,University of British Columbia | Moreno L.A.,University of Zaragoza
Bone | Year: 2010

Bone mass is a key determinant of fracture risk. Maximizing bone mineral mass during childhood and adolescence may contribute to fracture risk reduction during adolescence and possibly in the elderly. Although more than 60% of the variance of peak bone mass (PBM), the amount of bone present in the skeleton at the end of its maturation process, is genetically determined, the remainder is likely influenced by factors amenable to positive intervention, such as adequate dietary intake of dairy products as a natural source of calcium and proteins, vitamin D, and regular weight-bearing physical activity. Low calcium and vitamin D intakes are associated with negative effects on bone, including suboptimal PBM acquisition. As suggested by intervention studies, regular intake of dairy products may have positive and possibly sustained effects on bone mineral mass gain, contributing thereby to fracture risk reduction. Further evidence from intervention studies suggests that weight-bearing physical activities, such as jumping, may contribute to bone mineral mass gain in children. Optimizing PBM acquisition through dietary and physical exercise measures may represent a valuable primary method for the prevention of fractures. © 2009 Elsevier Inc. All rights reserved.

De La Escosura-Muniz A.,Biosensors | De La Escosura-Muniz A.,University of Zaragoza | Merkoci A.,Biosensors | Merkoci A.,Catalan Institution for Research and Advanced Studies
Electrochemistry Communications | Year: 2010

A novel device and methodology for the rapid and simple label-free electrochemical detection of proteins based on screen-printed carbon electrodes (SPCEs) modified with nanoporous Al2O3 membranes is reported. The nanoporous membranes are functionalized with antibodies and followed by the immunorecognition event that gives rise to the pore blocking. The blockage inside the nanochannels is fast, pore size dependent and easy to be detected by measuring the decrease in the differential pulse voltammetric (DPV) peak current of the [Fe(CN6)]4-/3- redox specie used as indicator. The developed nanoporous membrane based device represents a simple biodetection alternative that can be extended in the future to several other immuno and DNA detection systems. © 2010 Elsevier B.V. All rights reserved.

Valles J.A.,University of Zaragoza
IEEE Journal of Quantum Electronics | Year: 2011

The performance of a highly Yb3+/Er3+ -codoped phosphate glass femtosecond-laser written waveguide amplifier is numerically analyzed using a macroscopic rate-equation propagation model where concentration-dependent rates for the interatomic migration-assisted energy-transfer mechanisms are considered. The Er3+ -upconversion rate is obtained by a rigorous microscopic statistical modeling of the migration-assisted homogeneous upconversion, and the concentration dependence of the experimental Yb3+-sensitization rate utilized reflects the presence of migration among the Yb3+ ions. The results of the amplifier gain dependence on the dopant concentrations illustrate the influence of migration and the need of a careful modeling of interatomic energy-transfer mechanisms for high-concentration rare-earth-doped fiber or waveguide active devices. © 2011 IEEE.

Sarker S.,University of Agder | Arauzo J.,University of Zaragoza | Nielsen H.K.,University of Agder
Energy Conversion and Management | Year: 2015

Small scale air-blown fluidized bed gasification of alfalfa and wheat straw pellets were conducted for semi-continuous solid feeding and range of operating conditions varied due to the modifications in equivalence ratio (ER) (0.20-0.35) achieved both by varying solid and air input. Alfalfa pellets displayed an improvement in several gasification variables such as gas lower heating value (∼4.1 MJ/Nm3), specific gas yield (1.66 Nm3/kg), cold gas efficiency (∼42%) and carbon conversion efficiency (∼72%) as ER maximized to 0.35 which was found optimum for this feedstock for the present course of experiments. Gasification parameters of wheat straw pellets on the other hand were characterized by a great degree of variation as the ER progressively increased. The optimum performance of this biomass was likely to achieve at ER = 0.30 when gas lower heating value and cold gas efficiency maximized to ∼4 MJ/Nm3 and ∼37% respectively. Moreover, a substantial drop in tar yield (58.7 g/Nm3) at this ER was also indicative to the optimal thermal conversion at this point of operation. Overall, both the feedstocks presented promising alternatives for utilization into the small-scale fluidized bed gasification which is increasingly emerging as a sustainable solution towards processing lignocellulosic biomass. © 2015 Elsevier Ltd. All rights reserved.

Arganda E.,University of Zaragoza | Herrero M.J.,Autonomous University of Madrid | Marcano X.,Autonomous University of Madrid | Weiland C.,Autonomous University of Madrid | Weiland C.,The University of Shimane
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2016

In this letter we study new relevant phenomenological consequences of the right-handed heavy neutrinos with masses at the O(1)TeV energy scale, working within the context of the Inverse Seesaw Model that includes three pairs of quasi-degenerate pseudo-Dirac heavy neutrinos. We propose a new exotic signal of these heavy neutrinos at the CERN Large Hadron Collider containing a muon, a tau lepton, and two jets in the final state, which is based on the interesting fact that this model can incorporate large Lepton Flavor Violation for specific choices of the relevant parameters, particularly, the neutrino Yukawa couplings. We will show here that an observable number of μτ. jj exotic events, without missing energy, can be produced at this ongoing run of the LHC. © 2015 The Authors.

Adell J.A.,University of Zaragoza
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences | Year: 2011

Let (yn)n≥0 be the sequence of Stieltjes constants appearing in the Laurent expansion of the Riemann zeta function. We obtain explicit upper bounds for γn|, whose order of magnitude is (Equation presented) as n tends to infinity. To do this, we use a probabilistic approach based on a differential calculus for the gamma process.

Conde J.,New University of Lisbon | de la Fuente J.M.,University of Zaragoza | Baptista P.V.,New University of Lisbon
Journal of Nanobiotechnology | Year: 2010

Molecular nanodiagnostics applied to cancer may provide rapid and sensitive detection of cancer related molecular alterations, which would enable early detection even when those alterations occur only in a small percentage of cells. The use of gold nanoparticles derivatized with thiol modified oligonucleotides (Au-nanoprobes) for the detection of specific nucleic acid targets has been gaining momentum as an alternative to more traditional methodologies. Here, we present an Au-nanoparticles based approach for the molecular recognition and quantification of the BCR-ABL usion transcript (mRNA), which is responsible for chronic myeloid leukemia (CML), and to the best of our knowledge it is the first time quantification of a specific mRNA directly in cancer cells is reported. This inexpensive and very easy to perform Au-nanoprobe based method allows quantification of unamplified total human RNA and specific detection of the oncogene transcript. The sensitivity settled by the Au-nanoprobes allows differential gene expression from 10 ng/μl of total RNA and takes less than 30 min to complete after total RNA extraction, minimizing RNA degradation. Also, at later stages, accumulation of malignant mutations may lead to resistance to chemotherapy and consequently poor outcome. Such a method, allowing for fast and direct detection and quantification of the chimeric BCR-ABL mRNA, could speed up diagnostics and, if appropriate, revision of therapy. This assay may constitute a promising tool in early diagnosis of CML and could easily be extended to further target genes with proven involvement in cancer development.© 2010 Conde et al; licensee BioMed Central Ltd.

Varona L.,University of Zaragoza | Sorensen D.,University of Aarhus
Genetics | Year: 2010

An analysis of mortality is undertaken in two breeds of pigs: Danish Landrace and Yorkshire. Zero-inflated and standard versions of hierarchical Poisson, binomial, and negative binomial Bayesian models were fitted using Markov chain Monte Carlo (MCMC). The objectives of the study were to investigate whether there is support for genetic variation for mortality and to study the quality of fit and predictive properties of the various models. In both breeds, the model that provided the best fit to the data was the standard binomial hierarchical model. The model that performed best in terms of the ability to predict the distribution of stillbirths was the hierarchical zero-inflated negative binomial model. The best fit of the binomial hierarchical model and of the zero-inflated hierarchical negative binomial model was obtained when genetic variation was included as a parameter. For the hierarchical binomial model, the estimate of the posterior mean of the additive genetic variance (posterior standard deviation in brackets) at the level of the logit of the probability of a stillbirth was 0:173(0:039)in Landrace and 0:202(0:048) in Yorkshire. The implications of these results from a breeding perspective are briefly discussed. Copyright © 2010 by the Genetics Society of America.

Julvez J.J.,University of Zaragoza | Boel R.K.,Ghent University
IEEE Transactions on Systems, Man, and Cybernetics Part A:Systems and Humans | Year: 2010

Traffic systems are often highly populated discrete event systems that exhibit several modes of behavior such as free flow traffic, traffic jams, stop-and-go waves, etc. An appropriate closed loop control of the congested system is crucial in order to avoid undesirable behavior. This paper proposes a macroscopic model based on continuous Petri nets as a tool for designing control laws that improve the behavior of traffic systems. The main reason to use a continuous model is to avoid the state explosion problem inherent to large discrete event systems. The obtained model captures the different operation modes of a traffic system and is highly compositional. In order to handle the variability of the traffic conditions, a model predictive control strategy is proposed and validated. © 2010 IEEE.

Giordano M.,University of Zaragoza | Peschanski R.,CEA Saclay Nuclear Research Center
Journal of High Energy Physics | Year: 2011

We perform the analysis of quark-antiquark Reggeon exchange in meson-meson scattering, in the framework of the gauge/gravity correspondence in a confining background. On the gauge theory side, Reggeon exchange is described as quark-antiquark exchange in the t channel between fast projectiles. The corresponding amplitude is represented in terms of Wilson loops running along the trajectories of the constituent quarks and antiquarks. The paths of the exchanged fermions are integrated over, while the "spectator" fermions are dealt with in an eikonal approximation. On the gravity side, we follow a previously proposed approach, and we evaluate the Wilson-loop expectation value by making use of gauge/gravity duality for a generic confining gauge theory. The amplitude is obtained in a saddle-point approximation through the determination near the confining horizon of a Euclidean "minimal surface with floating boundaries", i.e., by fixing the trajectories of the exchanged quark and antiquark by means of a minimisation procedure, which involves both area and length terms. After discussing, as a warm-up exercise, a simpler problem on a plane involving a soap film with floating boundaries, we solve the variational problem relevant to Reggeon exchange, in which the basic geometry is that of a helicoid. A compact expression for the Reggeon-exchange amplitude, including the effects of a small fermion mass, is then obtained through analytic continuation from Euclidean to Minkowski space-time. We find in particular a linear Regge trajectory, corresponding to a Regge-pole singularity supplemented by a logarithmic cut induced by the non-zero quark mass. The analytic continuation leads also to companion contributions, corresponding to the convolution of the same Reggeon-exchange amplitude with multiple elastic rescattering interactions between the colliding mesons.

Chinesta F.,University of Nantes | Ammar A.,CNRS Rheology Laboratory | Cueto E.,University of Zaragoza
International Journal for Numerical Methods in Engineering | Year: 2010

In this paper the coupling of a parabolic model with a system of local kinetic equations is analyzed. A space-time separated representation is proposed for the global model (this is simply the radial approximation proposed by Pierre Ladeveze in the LATIN framework (Non-linear Computational Structural Mechanics. Springer: New York, 1999)). The originality of the present work concerns the treatment of the local problem, that is first globalized (in space and time) and then fully globalized by introducing a new coordinate related to the different species involved in the kinetic model. Thanks to the non-incremental nature of both discrete descriptions (the local and the global one) the coupling is quite simple and no special difficulties are encountered by using heterogeneous time integrations. © 2009 John Wiley & Sons, Ltd.

Viveros-Ceballos J.L.,Autonomous University of the State of Morelos | Cativiela C.,University of Zaragoza | Ordonez M.,Autonomous University of the State of Morelos
Tetrahedron Asymmetry | Year: 2011

The one-pot three-component reaction of 2-formylbenzoic acid with (S)- and (R)-methylbenzylamine and dimethyl phosphite (Kabachnik-Fields reaction) proceeded in short reaction times under solvent and catalyst free-conditions to afford the corresponding (3R,1′S)- and (3S,1′R)-isoindolin-1-one-3- phosphonates 3, respectively, in good yield and with high diastereoselectivity (95:5 dr). The use of a solvent decreases the diastereoselectivity and slows the reaction rate. The reaction rate was also influenced by CO2H functionality through protonation of the imine intermediate. The absolute configuration at the new stereogenic center was determined by X-ray crystal analysis, and a mechanism was proposed to explain the high diastereoselectivity. © 2011 Elsevier Ltd. All rights reserved.

Lanas A.,University of Zaragoza | Boers M.,VU University Amsterdam | Nuevo J.,Astrazeneca
Annals of the Rheumatic Diseases | Year: 2013

Objectives: Data concerning rates of gastrointestinal (GI) events in non-steroidal anti-inflammatory drug (NSAID) users derive mainly from clinical trials. The EVIDENCE study quantified the incidence of symptomatic uncomplicated and/or complicated GI events in at-risk European patients treated with NSAIDs in real-life practice. Methods: This non-interventional study assessed 4144 adults with at least one GI risk factor who recently initiated NSAID therapy for osteoarthritis (85%), rheumatoid arthritis (11%), ankylosing spondylitis (3%) or a combination (1%). Patient characteristics and medical history were collected from medical records. GI events (upper and lower) were recorded at in-clinic visits during 6 months' follow-up. Results: Mean time on index NSAID at enrolment was 33 days. The incidence (per 100 person-years) was 18.5 per 100 person-years for uncomplicated GI events and 0.7 per 100 person-years for complicated GI events. Upper GI events were far more common (12%) than lower GI events (1%) during study follow-up (median 182 days (range 61-320)). Other reported rates for cardiovascular, anaemia or non-GI events were much less frequent. A minority (28%) of patients had ongoing proton pump inhibitor use at enrolment, with strong variation by practice and country. Conclusions: EVIDENCE is the largest prospective study of the real-life management of European patients treated with NSAIDs for rheumatic diseases and at increased GI risk. It shows that GI events from the upper GI tract are far more common than those from the lower GI tract. It also shows adherence to guidelines for gastroprotection is generally low. © 2013 BMJ Publishing Group Ltd & European League Against Rheumatism.

Diaz Diaz D.,University of Regensburg | Diaz Diaz D.,University of Zaragoza | Kuhbeck D.,University of Regensburg | Koopmans R.J.,Dow Chemical Company
Chemical Society Reviews | Year: 2011

As part of a continuing scientific challenge, a substantial effort during the past few decades has been devoted towards altering the selectivity of chemical transformations by arranging the potential reactants in a number of organized and confining media. Such systems, having features significantly different from those of isotropic solutions, include, for example, micelles, microemulsions, molecular aggregates, liquid crystals, and zeolites. Among these materials, stimuli-response gels constitute another important class of nanostructured and dynamic systems with high active surface areas and remarkable diffusion properties. Within this group, polymer gels have been traditionally used to obtain catalytic and reactive soft materials. Moreover, gels made of low-molecular-weight compounds represent a major novelty in this area as potential soft-vessels to carry out chemical reactions with control on product selectivity. In addition, the possibility of integrating switchable catalytic functions in both organo- and hydrogels shall accelerate the development of robust platforms for the 'bottom-up' tailor-fabrication of more sophisticated functional materials. The present critical review reports on the most important results published during the last decade regarding the use of 'smart' gels that has displayed promising properties as selective soft-nanoreactors and/or heterogeneous recyclable catalysts (152 references). © 2011 The Royal Society of Chemistry.

Luesma M.J.,University of Zaragoza | Luesma M.J.,Aragon Health Research Institute IIS Aragon | Gherghiceanu M.,Victor Babes National Institute of Pathology | Popescu L.M.,University of Bucharest | Popescu L.M.,Victor Babes National Institute of Pathology
Journal of Cellular and Molecular Medicine | Year: 2013

The potential of stem cell (SC) therapies for eye diseases is well-recognized. However, the results remain only encouraging as little is known about the mechanisms responsible for eye renewal, regeneration and/or repair. Therefore, it is critical to gain knowledge about the specific tissue environment (niches) where the stem/progenitor cells reside in eye. A new type of interstitial cell-telocyte (TC) (www.telocytes.com) was recently identified by electron microscopy (EM). TCs have very long (tens of micrometres) and thin (below 200 nm) prolongations named telopodes (Tp) that form heterocellular networks in which SCs are embedded. We found TCs by EM and electron tomography in sclera, limbus and uvea of the mouse eye. Furthermore, EM showed that SCs were present in the anterior layer of the iris and limbus. Adhaerens and gap junctions were found to connect TCs within a network in uvea and sclera. Nanocontacts (electron-dense structures) were observed between TCs and other cells: SCs, melanocytes, nerve endings and macrophages. These intercellular 'feet' bridged the intercellular clefts (about 10 nm wide). Moreover, exosomes (extracellular vesicles with a diameter up to 100 nm) were delivered by TCs to other cells of the iris stroma. The ultrastructural nanocontacts of TCs with SCs and the TCs paracrine influence via exosomes in the epithelial and stromal SC niches suggest an important participation of TCs in eye regeneration. © 2013 The Authors. Journal of Cellular and Molecular Medicine Published by Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.

Balsa E.,Hospital Universitario Of La Princesa | Szklarczyk R.,Radboud University Nijmegen | Landazuri M.O.,Hospital Universitario Of La Princesa | Enriquez J.A.,University of Zaragoza
Cell Metabolism | Year: 2012

The oxidative phosphorylation system is one of the best-characterized metabolic pathways. In mammals, the protein components and X-ray structures are defined for all complexes except complex I. Here, we show that NDUFA4, formerly considered a constituent of NADH Dehydrogenase (CI), is instead a component of the cytochrome c oxidase (CIV). Deletion of NDUFA4 does not perturb CI. Rather, proteomic, genetic, evolutionary, and biochemical analyses reveal that NDUFA4 plays a role in CIV function and biogenesis. The change in the attribution of the NDUFA4 protein requires renaming of the gene and reconsideration of the structure of CIV. Furthermore, NDUFA4 should be considered a candidate gene for CIV rather than CI deficiencies in humans. © 2012 Elsevier Inc.

Martinez E.,University of Zaragoza
Journal of Geometric Mechanics | Year: 2015

The equations for the critical points of the action functional defined by a Lagrangian depending on higher-order derivatives of admissible curves on a Lie algebroid are found. The relation with Euler-Poincaré and Lagrange Poincaré type equations is studied. Reduction and reconstruction results for such systems are established. © American Institute of Mathematical Sciences

Martinez-Lera S.,LITEC CSIC Spanish Council for Scientific Research | Ballester J.,University of Zaragoza
Energy | Year: 2010

The design of capacity and operation of CHCP (combined heat, cooling and power) plants applied to HVAC (heating, ventilation and air conditioning) in buildings entails a considerable difficulty, because efficiency and economic aspects frequently interact in a complex way. Due to the strong fluctuations in thermal demands, the evaluation of a given design usually requires detailed simulations and a significant amount of input data. This paper proposes simplified approaches to estimate the main parameters characterising the thermal performance of the plant (ATD e method) as well as to identify optimal designs for a given application under certain encouragement policies (annual PES (primary energy savings) strategy). In the ATD e method, the duration curve of ATD (aggregated thermal demand) is used to estimate, among others, the amount of heat and cooling effectively supplied to the final user for a given design of the plant. This procedure serves to achieve a quick, global evaluation of the thermal performance of CHP (combined heat and power) or CHCP plants with little computational effort. The annual PES strategy searches the optimal values for the engine capacity, the OP (operation period) or both for CHP and CHCP plants in a particular application, defined by its energy demands. Both methods have demonstrated a notably good performance in several test cases with different patterns of the thermal demands. © 2010 Elsevier Ltd.

Delot T.,University of Valenciennes and HainautCambresis | Cenerario N.,University of Valenciennes and HainautCambresis | Ilarri S.,University of Zaragoza
Transportation Research Part C: Emerging Technologies | Year: 2010

In vehicular ad hoc networks (VANETs), different types of information can be useful to drivers. Such networks are highly dynamic due to both the movements of the vehicles and the short range of the wireless communications. Thus, the information exchanges between vehicles about relevant information can only rely on short interactions. Therefore, an efficient mechanism to manage and disseminate the relevant information is required. Specifically, we present in this paper a system for data sharing in vehicular networks, which we call Vehicular Event Sharing with a mobile Peer-to-peer Architecture (VESPA). In this system, a new technique based on the concept of Encounter Probability is proposed for vehicles to share information using vehicle-to-vehicle communications. The objective is to facilitate the dissemination of information between vehicles when they meet each other, taking into account the relevance of the data to the drivers. Besides, the relevance must also be considered to inform a driver about the interesting events. Moreover, our proposal takes into account any type of event (e.g., available parking spaces, obstacles in the road, information relative to the coordination of vehicles in emergency situations, etc.) in the network. An experimental evaluation and the implemented prototype show the interest of the system. © 2009 Elsevier Ltd.

Ranada M.F.,University of Zaragoza
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2016

The superintegrability of two-dimensional Hamiltonians with a position dependent mass (pdm) is studied (the kinetic term contains a factor m that depends of the radial coordinate). First, the properties of Killing vectors are studied and the associated Noether momenta are obtained. Then the existence of several families of superintegrable Hamiltonians is proved and the quadratic integrals of motion are explicitly obtained. These families include, as particular cases, some systems previously obtained making use of different approaches. We also relate the superintegrability of some of these pdm systems with the existence of complex functions endowed with interesting Poisson bracket properties. Finally the relation of these pdm Hamiltonians with the Euclidean Kepler problem and with the Euclidean harmonic oscillator is analyzed. © 2016

Chen Y.,CAS Institute of Geology and Geophysics | Zhang Z.,CAS Institute of Geology and Geophysics | Sun C.,Chinese Institute of Crustal Dynamics | Badal J.,University of Zaragoza
Gondwana Research | Year: 2013

In addition to crustal thickening, distinctly different mechanisms have been suggested to accommodate the huge convergences caused by the continental collision between India and Eurasia. As the transition zone between the two grand tectonic domains of Asia, the Tethys and the Pacific, east Tibet and its surrounding regions are the ideal places to study continental deformation. Pervasive rock deformation may produce anisotropy on the scale of seismic wavelengths; thus, seismic anisotropy provides insight into the deformation of the crust and mantle beneath tectonically active domains. In this study, we calculated receiver function pairs of radial- and transverse-components at 98 stations located in Sichuan and Yunnan provinces, China. We selected 7423 pairs with high signal-to-noise ratio (SNR) and unambiguous Moho converted Ps phases (Pms) to measure the Pms splitting owing to the crustal anisotropy. Both the crustal thickness and the average crustal Vp/Vs ratio were calculated simultaneously by the H. k stacking method. The geodynamic implications were also investigated in relation to surface geological features, GPS velocities, absolute plate motion (APM), SKS/SKKS splitting, and other seismological observations. In addition to the fast polarization directions (FPDs) of the crustal anisotropy, we observed a conspicuous sharper clockwise rotation around the eastern Himalayan syntaxis than was revealed by GPS velocities. The distributed FPDs within and near the main active fault zones also favored the directions parallel to the faults. This implied that the deformation of a continuous medium revealed by GPS motions is a proxy for the deformation of the brittle shallow crust only, while the main active faults and the deep crustal interiors both play important roles in the deep deformation. Our results suggest that the deformation between the crust and upper mantle within the northernmost section of the Indochina block is decoupled due to the large difference in the directions between the observations related to the crust (GPS and crustal anisotropy) and mantle (APM and mantle anisotropy). Focusing on the transition zone between the plateau and the South China and Indochina blocks, we suggest that the motion of the Central Yunnan sub-block is a southeastward extrusion by way of tectonic escape. There is less deformation in the deep crust and the motion is controlled by the active boundary faults of the Ailaoshan-Red River shear zone to the west and the Xianshuihe-Xiaojiang fault to the east; the lower crustal flow within the plateau southeastward reached the Lijiang-Xiaojinhe fault, but further south it was obstructed by the Central Yunnan sub-block. © 2012 International Association for Gondwana Research.

Iturrate I.,University of Zaragoza
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference | Year: 2010

Recent works suggest that several human cognitive processes elicited during the observation and monitoring of tasks developed by others can be detected in real time. These works have also demonstrated that human brain activity can be used to recover from machine errors, and as reward signals to teach a simulated robot how to perform given tasks. This paper studies the elicitation of this activity during the operation of a real robot. Experimental results have been obtained with 4 participants observing the operation of a 5 d.o.f. robotic arm performing correct/incorrect reaching tasks, while an EEG system recorded their brain activity. The results give evidence that the brain areas that play a role in detection and monitoring of errors also play a role when observing the operation of a real robot, that a brain discriminative response is elicited during the observation of a correct/incorrect operation of a real robot, and that it is possible to learn a classifier that provides online categorization with high accuracy (80%).

Alvarez S.,University of Barcelona | Menjon B.,University of Zaragoza
Angewandte Chemie - International Edition | Year: 2014

Weak yet influential: Fluorocarbons, the least coordinating of all halocarbons, establish secondary coordinative interactions with f elements. These interactions affect the stereochemistry of the complexes and provide examples of coordination polyhedra along distortion paths not seen before (see graphic). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chan F.K.L.,Chinese University of Hong Kong | Lanas A.,University of Zaragoza | Scheiman J.,University of Michigan | Berger M.F.,Pfizer | And 2 more authors.
The Lancet | Year: 2010

Background Cyclo-oxygenase (COX)-2-selective non-steroidal anti-inflammatory drugs (NSAIDs) and non-selective NSAIDs plus a proton-pump inhibitor (PPI) have similar upper gastrointestinal outcomes, but risk of clinical outcomes across the entire gastrointestinal tract might be lower with selective drugs than with non-selective drugs. We aimed to compare risk of gastrointestinal events associated with celecoxib versus diclofenac slow release plus omeprazole. aMethods We undertook a 6-month, double-blind, randomised trial in patients with osteoarthritis or rheumatoid arthritis at increased gastrointestinal risk at 196 centres in 32 countries or territories. Patients tested negative for Helicobacter pylori and were aged 60 years and older or 18 years and older with previous gastroduodenal ulceration. We used a computer-generated randomisation schedule to assign patients in a 1:1 ratio to receive celecoxib 200 mg twice a day or diclofenac slow release 75 mg twice a day plus omeprazole 20 mg once a day. Patients and investigators were masked to treatment allocation. The primary endpoint was a composite of clinically significant upper or lower gastrointestinal events adjudicated by an independent committee. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00141102. Findings 4484 patients were randomly allocated to treatment (2238 celecoxib; 2246 diclofenac plus omeprazole) and were included in intention-to-treat analyses. 20 (0·9%) patients receiving celecoxib and 81 (3·8%) receiving diclofenac plus omeprazole met criteria for the primary endpoint (hazard ratio 4·3, 95% CI 2·6-7·0; p<0·0001). 114 (6%) patients taking celecoxib versus 167 (8%) taking diclofenac plus omeprazole withdrew early because of gastrointestinal adverse events (p=0·0006). Interpretation Risk of clinical outcomes throughout the gastrointestinal tract was lower in patients treated with a COX-2-selective NSAID than in those receiving a non-selective NSAID plus a PPI. These findings should encourage review of approaches to reduce risk of NSAID treatment. Funding Pfizer Inc.

Lanas A.,University of Zaragoza | Wu P.,University of Ottawa | Medin J.,Astrazeneca | Mills E.J.,University of Ottawa
Clinical Gastroenterology and Hepatology | Year: 2011

Background & Aims: We performed a meta-analysis of data from randomized trials to estimate the risk of all-cause mortality and bleeding (and especially gastrointestinal [GI] bleeding) in patients treated with low doses of acetylsalicylic acid (ASA) (75-325 mg/d), alone or in combination with other medications. Methods: We searched 10 electronic databases (until October 2010) and collected data on adverse events in randomized controlled studies that evaluated low doses of ASA, alone (35 trials) or in combination with anticoagulants (18 trials), clopidogrel (5 trials), or proton pump inhibitors (PPIs; 3 trials). We analyzed data using random-effects meta-analysis and meta-regression, applying Peto's odds ratio (OR) for adverse events. Results: Low doses of ASA alone decreased the risk for all-cause mortality (relative risk, 0.93, 95% confidence interval [CI], 0.87-0.99), largely because of effects in secondary prevention populations. The risk of major GI bleeding increased with low doses of ASA alone (OR, 1.55; 95% CI, 1.27-1.90), compared with inert control reagents. The risk increased when ASA was combined with clopidogrel, compared with aspirin alone (OR, 1.86; 95% CI, 1.49-2.31), anticoagulants vs low doses of ASA alone (OR, 1.93; 95% CI, 1.42-2.61), or in studies that included patients with a history of GI bleeding or of longer duration. Importantly, PPI use reduced the risk for major GI bleeding in patients given low doses of ASA (OR, 0.34; 95% CI, 0.21-0.57). Conclusions: In a meta-analysis, low doses of ASA increased the risk for GI bleeding; risk increased with accompanying use of clopidogrel and anticoagulant therapies, but decreased in patients who took PPIs. © 2011 AGA Institute.

Correa G.J.,Luis Amigo University Foundation | Yusta J.M.,University of Zaragoza
Energy Conversion and Management | Year: 2014

In this paper the authors apply methodological strategies for the structural vulnerability assessment in high voltage power networks based upon the combination of power flow models and scale-free graph statistic indexes. Thus, it is possible to study risk scenarios based on events that may trigger cascading failures within a power system. The usefulness of graph theory techniques has been validated on previous works of the authors, and may be applied in analysis of the vulnerability of different power electric networks. A case study for vulnerability analysis is carried out through methodologies that allow comparison on random error and deliberate attack tolerance evaluation in transmission electric systems from countries like Colombia and Spain. Such vulnerability assessment methodology takes into account the current conditions of the power networks (base case), as well as the impact of expansion plans into infrastructures as defined by their governments. Consequently, the authors show the advantage on the use of graph theory based techniques for vulnerability analysis of electrical power systems. © 2013 Elsevier Ltd. All rights reserved.

Mora J.L.,University of Zaragoza | Lazaro R.,CSIC - Estacion Experimental De Zonas Aridas
Geoderma | Year: 2014

Objective: We investigated the temporal variation of soil bulk density (BD) in a semiarid Macrochloa tenacissima grassland where BD plays a key role in the soil-plant feedback mechanisms that are responsible for the patchy distribution of vegetation. Methods: We used the core method to analyse the soil BD in two experimental sites in microsites that were representative of the spatial heterogeneity of soils and vegetation. The study was performed over two years, in winter (three times) and summer (twice). We studied the changes in BD in relation to the rainfall and to the soil properties that describe or affect the soil structural conditions, such as soil moisture, particle-size, clay mineralogy, the contents of various organic carbon fractions and certain microaggregation indices. Results: We found a consistent temporal variation in BD, which was lower in winter (1.22±0.02g/cm3, average±SEM) than in summer (1.33±0.02g/cm3) and depended on the rainfall in the weeks before sampling. The greatest change was observed during the first year of study, when the wettest winter and the driest summer occurred. The variation of BD was most pronounced in the mounds developed under senescent plants (+16.7% average increase from winter to summer), intermediate under adult plants and in the residual mounds (+8.9%) and was weak in the soils of the bare areas or under young plants (+5.1%). This implies that the microtopography should get steeper in winter and flatter in summer. The largest changes in BD were correlated with variables representing organic matter and its action in adhering soil particles. Conclusion: We observed consistent temporal variations in BD that were spatially heterogeneous and related to wet conditions in the soils studied. Research is needed to establish the mechanisms responsible for the changes in BD, which may include greater activity of roots and fauna during the wet season and the enrichment in labile organic fractions that are hygroscopic and can bind soil particles into temporary aggregates. Practice implications: Spatially heterogeneous temporal variation in BD must be taken into account in inventories of soil nutrients, water or carbon. Moreover, it implies an increased porosity under vegetated patches just when the soil receives the most rainfall, resulting in a positive feedback of plant growth and mound formation. This mechanism might be added to those already described for plant-soil feedbacks in dry lands. © 2014 Elsevier B.V.

Used J.,Rey Juan Carlos University | Martin J.C.,University of Zaragoza
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2010

We analyze the chaotic emission of an erbium-doped fiber laser with sine-wave pump power modulation for different modulation frequencies and modulation indexes. For each working condition considered, the template which summarizes the corresponding chaotic attractor has been determined by means of topological analysis techniques. The variety of templates obtained is much wider than in previous works: apart from horseshoes, reverse horseshoes, or jellyroll structures with different global torsions, two more kinds of structures have been found. Particularly, one is especially notable as its folding mechanism does not fit the rolling scheme valid for all templates found in former experimental studies. Apart from strengthening the usefulness of templates as convenient objects for characterization of chaotic attractors, the interest of these results lies in the identification of folding mechanisms for chaos generation not found in nature up to now. © 2010 The American Physical Society.

Gonzalez-Tudela A.,Autonomous University of Madrid | Martin-Cano D.,Autonomous University of Madrid | Moreno E.,Autonomous University of Madrid | Martin-Moreno L.,University of Zaragoza | And 2 more authors.
Physical Review Letters | Year: 2011

We investigate qubit-qubit entanglement mediated by plasmons supported by one-dimensional waveguides. We explore both the situation of spontaneous formation of entanglement from an unentangled state and the emergence of driven steady-state entanglement under continuous pumping. In both cases, we show that large values for the concurrence are attainable for qubit-qubit distances larger than the operating wavelength by using plasmonic waveguides that are currently available. © 2011 The American Physical Society.

Garcia-Vidal F.J.,Autonomous University of Madrid | Martin-Moreno L.,University of Zaragoza | Ebbesen T.W.,University of Strasbourg | Kuipers L.,FOM Institute for Atomic and Molecular Physics
Reviews of Modern Physics | Year: 2010

This review provides a perspective on the recent developments in the transmission of light through subwavelength apertures in metal films. The main focus is on the phenomenon of extraordinary optical transmission in periodic hole arrays, discovered over a decade ago. It is shown that surface electromagnetic modes play a key role in the emergence of the resonant transmission. These modes are also shown to be at the root of both the enhanced transmission and beaming of light found in single apertures surrounded by periodic corrugations. This review describes both the theoretical and experimental aspects of the subject. For clarity, the physical mechanisms operating in the different structures considered are analyzed within a common theoretical framework. Several applications based on the transmission properties of subwavelength apertures are also addressed. © 2010 The American Physical Society.

Wood R.,University of Edinburgh | Zhuravlev A.Y.,University of Zaragoza | Zhuravlev A.Y.,Russian Academy of Sciences
Earth-Science Reviews | Year: 2012

Assembly of the necessary biochemical machinery for biomineralisation long-predated the appearance and rapid diversification of metazoan skeletons in the late Ediacaran to Middle Cambrian (~. 550-520. million years ago (Ma)), and the independent acquisition of skeletons of differing mineralogies suggests a trigger that conferred selective advantage to possession of a skeleton even though this involved physiological cost.The cost-benefit ratio of biomineralisation has changed over geological time, varying not only with the availability of precursor ions in seawater, but also with evolutionary innovations, as the energy required to produce a skeleton will change as a function of community ecology, particularly with increases in predation pressure.Here, we demonstrate that during the Cambrian Radiation the choice of biomineral was controlled by an interaction between changing seawater chemistry and evolving ecology. The record also reveals the successive skeletonisation of groups with increasing levels of activity from the Ediacaran to Middle Cambrian. The oldest (~550-540Ma) biomineralised organisms were sessile, and preferentially formed low-cost, simple, skeletons of either high-Mg calcite coincident with high mMg:Ca and/or low pCO2 (aragonite seas), or phosphate during with a well-documented phosphogenic event. More elaborate, but tough and protective, aragonitic skeletons appeared from ~540Ma, dominantly in motile benthos (mostly stem- and crown-group Lophotrochozoa). The first low-Mg calcite skeletons of novel organic-rich composite materials (e.g. trilobites) did not appear until the late early Cambrian (~526Ma), coincident with the first onset of low mMg:Ca and/or high pCO2 (calcite seas). Active, bentho-pelagic predatory groups (vertebrates, chaetognaths, some arthropods) appearing mainly in the late early Cambrian preferentially possessed phosphatic skeletons, which were more stable at the low pH ranges of extracellular fluids associated with intense activity and high-energy ecologies.These trends suggest that the increasing physiological cost of biomineralisation in successively more demanding metabolisms was offset by the increased chance of survival conferred by a protective skeleton, so indicating a driver of escalating community ecology, in particular an increase in predation pressure. © 2012.

Belhaj A.,Center National Of Lenergie | Segui A.,University of Zaragoza
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2010

Using D-brane configurations on the K3 surface, we give six-dimensional type IIA stringy realizations of the Quantum Hall Effect (QHE) in 1+2 dimensions. Based on the vertical and horizontal lines of the K3 Hodge diamond, we engineer two different stringy realizations. The vertical line presents a realization in terms of D2 and D6-branes wrapping the K3 surface. The horizontal one is associated with hierarchical stringy descriptions obtained from a quiver gauge theory living on a stack of D4-branes wrapping intersecting 2-spheres embedded in the K3 surface with deformed singularities. These geometries are classified by three kinds of the Kac-Moody algebras: ordinary, i.e. finite dimensional, affine and indefinite. We find that no stringy QHE in 1+2 dimensions can occur in the quiver gauge theory living on intersecting 2-spheres arranged as affine Dynkin diagrams. Stringy realizations of QHE can be done only for the finite and indefinite geometries. In particular, the finite Lie algebras give models with fractional filling fractions, while the indefinite ones classify models with negative filling fractions which can be associated with the physics of holes in the graphene. © 2010.

Gallardo J.,University of Zaragoza | Bravo C.,University of Castilla - La Mancha | Redondo M.A.,University of Castilla - La Mancha
Journal of Network and Computer Applications | Year: 2012

Collaborative modeling tools are useful for many tasks within design or learning processes. However, they are difficult to build and are usually domain-specific. In response to this situation, we propose a model-driven method for the development of domain-independent collaborative modeling tools. This method consists of a methodological framework, a conceptual framework and a technological framework. The methodological framework defines the phases to be carried out when applying the method, whilst the conceptual framework is made up of the meta-models used in the method and the transformation processes established between them. Finally, the technological framework consists of the integration of some plug-ins from the Eclipse Modeling Project with some add-ons which provide collaborative functionality. Some case studies that exemplify this development method for specific domains are explained in detail, together with comparisons with similar approaches. Thus, an initial evaluation of this approach is provided and some advantages over those other approaches are identified. A further evaluation process in the form of an empirical study of use has also been carried out. Hence, the method proves to be useful for any user who does not have advanced knowledge of groupware programming and who needs to use a collaborative modeling tool in his/her work. Moreover, each framework implies a contribution that can be used in different contexts. © 2011 Elsevier Ltd. All rights reserved.

This paper presents an overview of the literature on kinematic and calibration models of parallel mechanisms, the influence of sensors in the mechanism accuracy and parallel mechanisms used as sensors. The most relevant classifications to obtain and solve kinematic models and to identify geometric and non-geometric parameters in the calibration of parallel robots are discussed, examining the advantages and disadvantages of each method, presenting new trends and identifying unsolved problems. This overview tries to answer and show the solutions developed by the most up-to-date research to some of the most frequent questions that appear in the modelling of a parallel mechanism, such as how to measure, the number of sensors and necessary configurations, the type and influence of errors or the number of necessary parameters.

Collado F.J.,University of Zaragoza
Solar Energy | Year: 2010

Accurate and simple models for the flux density reflected by an isolated heliostat should be one of the basic tools for the design and optimization of solar power tower systems. In this work, the ability and the accuracy of the Universidad de Zaragoza (UNIZAR) and the DLR (HFCAL) flux density models to fit actual energetic spots are checked against heliostat energetic images measured at Plataforma Solar de Almería (PSA). Both the fully analytic models are able to acceptably fit the spot with only one-point fitting, i.e., the measured maximum flux. As a practical validation of this one-point fitting, the intercept percentage of the measured images, i.e., the percentage of the energetic spot sent by the heliostat that gets the receiver surface, is compared with the intercept calculated through the UNIZAR and HFCAL models. As main conclusions, the UNIZAR and the HFCAL models could be quite appropriate tools for the design and optimization, provided the energetic images from the heliostats to be used in the collector field were previously analyzed. Also note that the HFCAL model is much simpler and slightly more accurate than the UNIZAR model. © 2010 Elsevier Ltd. All rights reserved.

Mohammadi A.H.,MINES ParisTech | Martinez-Lopez J.F.,University of Zaragoza | Richon D.,MINES ParisTech
Chemical Engineering Science | Year: 2010

In this communication, we have developed a feed-forward artificial neural network algorithm for estimating dissociation pressures of the binary clathrate hydrates of tetrahydrofuran+methane, carbon dioxide or nitrogen as a function of temperature and concentration of tetrahydrofuran in the aqueous solution below/equal its stoichiometric concentration (i.e., 0.056 mole fraction). In order to develop this algorithm, the most reliable experimental data reported in the literature on the dissociation pressures of the aforementioned binary hydrates have been used. Moreover, we report few experimental data on the dissociation pressures of the binary hydrates of tetrahydrofuran+carbon dioxide or nitrogen at 0.011 mole fraction of tetrahydrofuran in aqueous solution, which were measured using an isochoric pressure-search method. The latter experimental data are used to verify the reliability of the corresponding experimental data reported in the literature. © 2010 Elsevier Ltd.

Gonzalez-Aguero A.,University of Zaragoza
Clinical Journal of Sport Medicine | Year: 2016

OBJECTIVE:: To describe cortical and trabecular volumetric bone mineral density (vBMD), bone mineral content (BMC), cross-sectional area (CSA), and bone strength indexes (BSIs) in adolescent endurance-trained cyclists (CYC) and compare them with controls (CON). DESIGN:: Descriptive cohort study. PARTICIPANTS:: Twenty-five male adolescent CYC and 17 CON. ASSESSMENT OF RISK FACTORS:: Peripheral quantitative computed tomography was used to evaluate proximal and distal sites of the radius and tibia. MAIN OUTCOME MEASURES:: Total, trabecular, and cortical BMC, vBMD, and CSA were measured. Also, cortical thickness, endosteal and periosteal circumferences, and different BSIs were calculated. Unadjusted analysis of variance and body weight-adjusted analysis of covariance tests were applied between cyclist and control groups. RESULTS:: Cyclists were almost 12% lighter than CON (P < 0.05). Unadjusted data showed lower distal total vBMD and proximal cortical BMC and vBMD in cyclists compared with CON at the radius (P < 0.05) and lower distal total and trabecular BMC, vBMD and bone area, proximal total and cortical BMC and vBMD, and cortical bone area at the tibia (P < 0.05). Body weight-adjusted data showed the same differences for distal total vBMD at the radius and total and trabecular BMC and vBMD at the tibia, diaphyseal radius cortical vBMD and tibia total vBMD, cortical BMC and area, and also for tibia cortical thickness and BSI. The rest of differences were no longer detectable and bone area at the distal radius become significantly higher in cyclist compared with CON (P < 0.05). CONCLUSIONS:: Adolescent CYC in this study showed lower values of BMC and vBMD at determined sites of the radius and tibia than CON, some of these differences were explained in part by their lower body weight. However, even further adjustment, some differences remained, which indicates that further longitudinal studies are needed to better understand if cycling influences these differences. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Meloni S.,Third University of Rome | Gomez-Gardenes J.,Rey Juan Carlos University | Gomez-Gardenes J.,University of Zaragoza
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2010

We present a mechanism to avoid congestion in complex networks based on a local knowledge of traffic conditions and the ability of routers to self-coordinate their dynamical behavior. In particular, routers make use of local information about traffic conditions to either reject or accept information packets from their neighbors. We show that when nodes are only aware of their own congestion state they self-organize into a hierarchical configuration that delays remarkably the onset of congestion although leading to a sharp first-order-like congestion transition. We also consider the case when nodes are aware of the congestion state of their neighbors. In this case, we show that empathy between nodes is strongly beneficial to the overall performance of the system and it is possible to achieve larger values for the critical load together with a smooth, second-order-like, transition. Finally, we show how local empathy minimize the impact of congestion as much as global minimization. Therefore, here we present an outstanding example of how local dynamical rules can optimize the system's functioning up to the levels reached using global knowledge. © 2010 The American Physical Society.

Alegre-Requena J.V.,University of Zaragoza
Synlett | Year: 2014

(A) Organocatalyst Sos and co-workers recently reported the asymmetric conjugate addition of different acetylacetoates to nitrostyrenes with high yields and enantioselectivities using immobilized squaramides.11 The most appealing aspect of this work is that the reactions were carried out successfully in batch and flow reactors, bringing this catalyst closer to industrial applications. Taylor and co-workers reported the use of a N,N-diarylsquaramide as a colorimetric sensor for anions such as fluoride and tosylate. The squaramide showed different colors depending on the anion present in a DMSO solution. This behavior seems to be in agreement with an enhanced acidity in comparison with ureas. (C) Cation Sensors Costa and co-workers developed a squaramide-based sensor for selective detection of Cu2+.12 When this compound chelates with Cu2+, a zwitterionic colored radical species is formed rapidly, allowing the visual etection of Cu2+. Interestingly, this compound can be used in water for the detection of Cu2+, displaying good selectivity for this cation over other metallic cations (D) Transmembrane Anion Transporters Gale and co-workers reported the use of squaramides as anion transporters across lipid bilayers, obtaining better results than their urea and thiourea analogues.5 This research opens a door for the use of squaramide-based drugs in the treatment of diseases caused by malfunctioning ion channels. (E) Antimalarial Agents Santos and co-workers synthesized squaramide aza vinyl sulfones that were shown to have antiplasmodial activities.6 These compounds could be used as medicines in the complex fight against malaria, an illness that infects millions of people every year and develops resistance to the drugs used in its treatment.13 ((F) Linkers for Biomolecules Luk and co-workers reported the coupling of peptides using squaramides as linkers.14 These reactions make squaramides suitable for modifying existing biomolecules, adding parts containing peptides to their structures. This peptide coupling is carried out using water as the solvent, which might make the use of this type of compound suitable for in vivo studies. © Georg Thieme Verlag Stuttgart, New York.

Low T.,IBM | Low T.,Yale University | Low T.,University of Minnesota | Roldan R.,CSIC - Institute of Materials Science | And 5 more authors.
Physical Review Letters | Year: 2014

Black phosphorus exhibits a high degree of band anisotropy. However, we find that its in-plane static screening remains relatively isotropic for momenta relevant to elastic long-range scattering processes. On the other hand, the collective electronic excitations in the system exhibit a strong anisotropy. Band nonparabolicity, due to interband couplings, leads to a plasmon frequency which scales as nβ, where n is the carrier concentration, and β<12. Screening and charge distribution in the out-of-plane direction are also studied using a nonlinear Thomas-Fermi model. © 2014 American Physical Society.

Miranda-de la Lama G.C.,Metropolitan Autonomous University | Villarroel M.,Polytechnic University of Mozambique | Maria G.A.,University of Zaragoza
Meat Science | Year: 2014

New developments in livestock transport within the pre-slaughter chain are discussed in terms of three logistic nodes: origin, stopovers and slaughterhouse. Factors as transport cost, haulier, truck specifications, micro-environment conditions, loading density, route planning, vehicle accidents and journey length are discussed as well as causes of morbidity, mortality, live weight and carcass damage. Taking into account current trends towards increased transport times, logistics stopovers and mixed transport, there is a need to develop systems of evaluation and decision-making that provide tools and protocols that can minimize the biological cost to animals, which may have been underestimated in the past. © 2014 Elsevier Ltd.

Maraver D.,Research Center for Energy Resources and Consumption | Royo J.,University of Zaragoza | Lemort V.,University of Liege | Quoilin S.,University of Liege
Applied Energy | Year: 2014

The present work is focused on the thermodynamic optimization of organic Rankine cycles (ORCs) for power generation and CHP from different average heat source profiles (waste heat recovery, thermal oil for cogeneration and geothermal). The general goal is to provide optimization guidelines for a wide range of operating conditions, for subcritical and transcritical, regenerative and non-regenerative cycles. A parameter assessment of the main equipment in the cycle (expander, heat exchangers and feed pump) was also carried out. An optimization model of the ORC (available as an electronic annex) is proposed to predict the best cycle performance (subcritical or transcritical), in terms of its exergy efficiency, with different working fluids. The working fluids considered are those most commonly used in commercial ORC units (R134a, R245fa, Solkatherm, n-Pentane, Octamethyltrisiloxane and Toluene). The optimal working fluid and operating conditions from a purely thermodynamic approach are limited by the technological constraints of the expander, the heat exchangers and the feed pump. Hence, a complementary assessment of both approaches is more adequate to obtain some preliminary design guidelines for ORC units. © 2013 Elsevier Ltd.

Bernardi S.,Centro Universitario Of La Defensa | Merseguer J.,University of Zaragoza | Petriu D.C.,Carleton University
ACM Computing Surveys | Year: 2012

The goal is to survey dependability modeling and analysis of software and systems specified with UML, with focus on reliability, availability, maintainability, and safety (RAMS). From the literature published in the last decade, 33 approaches presented in 43 papers were identified. They are evaluated according to three sets of criteria regarding UML modeling issues, addressed dependability characteristics, and quality assessment of the surveyed approaches. The survey shows that more works are devoted to reliability and safety, fewer to availability and maintainability, and none to integrity. Many methods support early life-cycle phases (from requirements to design). More research is needed for tool development to automate the derivation of analysis models and to give feedback to designers. © 2012 ACM.

Davis J.J.,VectorNav Technologies, LLC | Avendano M.E.,University of Zaragoza | Mortari D.,Texas A&M University
Celestial Mechanics and Dynamical Astronomy | Year: 2013

Flower Constellations (FCs) have been extensively studied for use in optimal constellation design. The Harmonic FCs (HFCs) subset, representing the symmetric configurations, have recently been reformulated into 2-D Lattice Flower Constellations (2D-LFCs), encompassing the complete set of HFCs. Elliptic orbits are generally avoided due to the deleterious effects of Earth's oblateness on the constellation, but here we present a novel concept for avoiding this problem and enabling more effective global coverage utilizing elliptic orbits. This new 3D Lattice Flower Constellations (3D-LFCs) framework generalizes the 2D-LFCs, Walker constellations, elliptical Walker constellations, and many of Draim's global coverage constellations. Previous studies have shown FCs can provide improved performance in global navigation over existing Global Navigation Satellite Systems (GNSS). We found a 3D-LFC design that improved the average positioning accuracy by 3.5 % while reducing launch Δ v requirements when compared to the existing Galileo GNSS constellation. © 2013 Springer Science+Business Media Dordrecht.

Avendano M.E.,University of Zaragoza | Davis J.J.,VectorNav Technologies, LLC | Mortari D.,Texas A&M University
Celestial Mechanics and Dynamical Astronomy | Year: 2013

The 2-D lattice theory of Flower Constellations, generalizing Harmonic Flower Constellations (the symmetric subset of Flower Constellations) as well as the Walker/ Mozhaev constellations, is presented here. This theory is a new general framework to design symmetric constellations using a 2× 2 lattice matrix of integers or by its minimal representation, the Hermite normal form. From a geometrical point of view, the phasing of satellites is represented by a regular pattern (lattice) on a two-Dimensional torus. The 2-D lattice theory of Flower Constellations does not require any compatibility condition and uses a minimum set of integer parameters whose meaning are explored throughout the paper. This general minimum-parametrization framework allows us to obtain all symmetric distribution of satellites. Due to the J2 effect this design framework is meant for circular orbits and for elliptical orbits at critical inclination, or to design elliptical constellations for the unperturbed Keplerian case. © 2013 Springer Science+Business Media Dordrecht.

Gadella B.M.,University Utrecht | Luna C.,University Utrecht | Luna C.,University of Zaragoza
Theriogenology | Year: 2014

Theriogenology has now a 40-year rich history on covering sperm biological aspects with a special emphasis on farm and husbandry animals. The major and most influential of these contributions will be placed into an evolutionary perspective of ongoing and intriguing progresses made in this field. Although many molecular details have been published, it is more the aim of this contribution to provide a guide through the main established aspects and concepts of sperm surface biology and refer only to major molecular players and mechanisms involved in sperm physiology. Those interested in more molecular details and in-depth knowledge can easily access the most relevant literature which is included here for reference purposes. With this approach, a logical and easy to follow buildup can be made of the general picture of sperm surface dynamics and of the ergonomics of sperm physiology and their function in mammalian fertilization. Understanding the ins and outs of sperm surface biology and the dynamics thereof, might challenge future researchers to design novel generation of better sperm-handling procedures. This could be beneficial for assisted reproductive technology and animal breeding industries. © 2014 Elsevier Inc.

Roubeau O.,University of Zaragoza
Chemistry - A European Journal | Year: 2012

One-dimensional coordination FeII polymers constructed through triple N1,N2-1,2,4-triazole bridges form a unique class of spin-crossover materials, the synthetic versatility of which allows tuning the spin-crossover properties, the design of gels, films, liquid crystals, and nanoparticles and single-particle addressing. This Minireview provides the first complete overview of these very attractive switchable materials and their most recent developments. The spin-crossover toolbox: A complete and concise overview of all the spin-crossover [Fe(Rtrz)3][A]x systems reported is provided (Rtrz is a 4-substituted-1,2,4-triazole; A=monovalent anion). The structural and magneto-optical properties of these one-dimensional coordination polymers are summarised, as well as their implementation into other phases of matter or nanostructured objects. The most relevant and recent developments based on this very attractive class of switchable materials are highlighted. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Laguna-Bercero M.A.,University of Zaragoza
Journal of Power Sources | Year: 2012

New and more efficient energy conversion systems are required in the near future, due in part to the increase in oil prices and demand and also due to global warming. Fuel cells and hybrid systems present a promising future but in order to meet the demand, high amounts of hydrogen will be required. Until now, probably the cleanest method of producing hydrogen has been water electrolysis. In this field, solid oxide electrolysis cells (SOEC) have attracted a great interest in the last few years, as they offer significant power and higher efficiencies compared to conventional low temperature electrolysers. Their applications, performances and material issues will be reviewed. © 2011 Elsevier B.V. All rights reserved.

Mochales T.,Instituto Geologico Y Minero Of Espana | Casas A.M.,University of Zaragoza | Pueyo E.L.,Instituto Geologico Y Minero Of Espana | Barnolas A.,Instituto Geologico Y Minero Of Espana
Journal of Structural Geology | Year: 2012

Despite the large amount of paleomagnetic and structural studies on fold and thrust belts, many key questions about rotational kinematics remain unsolved (pace of rotation, subsequent accommodation of the hanging wall, etc.). Excellent exposure conditions and syntectonic sedimentation related to the growth of oblique structures in the Southern Pyrenees allow an accurate investigation that sheds light on the rotational kinematics of thrust systems. Fifty-nine paleomagnetic sites (819 specimens) are homogeneously distributed in both limbs along the marine and continental sedimentary sequences contemporary with the uplift of the Boltaña anticline and its post-folding evolution. They indicate a clockwise rotation of about 52° during Ypresian to Priabonian times. Primary, stable (350°-580°C), pre-folding magnetization in the Eocene rocks is attested by a positive fold test and the antipodality proof, with magnetite and iron sulphide traces as magnetic carriers. Rotation velocity fits a logarithmic model and shows a low rate during the Ilerdian-Middle Lutetian interval (ca. 1°/m.y.) and much higher (up to 10°/m.y.) in the Late Lutetian-Priabonian interval. Most of the clockwise rotation of the Boltaña anticline can therefore be constrained within the 42-35M.a. interval (partially post-folding), indicating a period of strong differential displacement in the southern Pyrenean Zone, probably related to the emplacement of the underlying External Sierras thrust sheets (Tozal-Alcanadre). © 2011 Elsevier Ltd.

Lanas A.,University of Zaragoza | Garcia-Tell G.,University of Valencia | Armada B.,Pfizer | Oteo-Alvaro A.,Service of Orthopedics
BMC Medicine | Year: 2011

Background: Prescription of non-steroidal anti-inflammatory drugs (NSAIDs) should be based on the assessment of both gastrointestinal (GI) and cardiovascular (CV) risk for the individual patient. We aimed to assess the GI/CV risk profile and the pharmacological management of patients with osteoarthritis (OA) in clinical practice.Methods: We conducted a cross-sectional, multicentre, observational study of consecutive OA patients that visited 1,760 doctors throughout the Spanish National Health System (NHS) in a single day. The presence of GI risk factors, CV histories, hypertension and current pharmacological treatments was recorded.Results: Of the 60,868 patients, 17,105 had a diagnosis of OA and were evaluable. The majority (93.4%) had more than one GI risk factor and 60.3% were defined to be at high-GI risk. Thirty-two percent had a history of CV events, 57.6% were treated with anti-hypertensive therapy and 22.6% had uncontrolled hypertension. One-fifth of patients were treated with non-NSAID therapies, whereas the remaining patients received NSAIDs. Non-selective NSAIDs (nsNSAID) plus proton pump inhibitor (PPI) or cyclooxigenase-2 (COX-2)-selective NSAIDs alone were more frequently prescribed in patients at increased GI risk. Patients with a positive CV history received nsNSAIDs or COX-2-selective NSAIDs in 41.3% and 31.7% of cases, respectively. When both the GI and CV histories were combined, 51% of the overall population was being prescribed drugs that were either not recommended or contraindicated.Conclusions: Over 90% of patients with OA are at increased GI and/or CV risk. In over half of these patients, the prescription of NSAIDs was not in accordance with current guidelines or recommendations made by regulatory agencies. © 2011 Lanas et al; licensee BioMed Central Ltd.

Puertolas J.A.,University of Zaragoza | Kurtz S.M.,Drexel University | Kurtz S.M.,Exponent, Inc.
Journal of the Mechanical Behavior of Biomedical Materials | Year: 2014

In this review we have evaluated the state of the art of CNT/UHMWPE and graphene/UHMWPE composites from four different points of view: mechanical properties, chemical stability, wear resistance and biocompatibility. The performance of these new carbonaceous composites allows us to conclude that these materials have overcome a first step on the way to developing into an alternative to the current HXLPEs used in orthopedic applications. © 2014 Elsevier Ltd.

Gil J.J.,University of Zaragoza
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

From an appropriate parameterization of the three-dimensional (3D) coherency matrix R that characterizes the second-order, classical states of polarization, the coherency matrices are classified and interpreted in terms of incoherent decompositions. The relevant physical quantities derived from R, such as the intensity, degree of polarimetric purity, the indices of polarimetric purity, angular momentum, degree of directionality, and degree of linear polarization, are identified and interpreted in light of the case study performed. The information provided by R about the direction of propagation is clarified and it is found that coherency matrices with rankR=2 do not always represent states with a well-defined direction of propagation. Moreover, the existence of 3D mixed states that cannot be decomposed into a superposition of a pure state, a two-dimensional (2D) unpolarized state, and a 3D unpolarized state is demonstrated. Appropriate representation and interpretation for all the different types of 3D coherency matrices are provided through physically consistent criteria. Under the approach proposed, the conventional 2D model arises naturally. © 2014 American Physical Society.

Agricultural systems are the greatest consumers of freshwater in the world and irrigation return flows are one of the main pollutants of water bodies. This paper analyzes the hydrologic dynamics and water quality (salinity and nitrate concentrations) of an aquifer belonging to a traditional irrigated land. The study was carried out for the hydrologic years of 2006, 2007 and 2008, relating changes in water quality with geological and agricultural characteristics of the evaluated irrigated land. The study reveals that the surface hydrological basin and groundwater hydrological basin do not coincide, so a contribution from the aquifer recharge by groundwater flow was added to the aquifer recharge by water drainage from the surface basin. Regarding water quality, 4% of the collected samples exceeded the value limit established for waters intended for irrigation (3.0 dS/m) and human consumption (2.5 dS/m). Concerning nitrates, 35% of the collected samples exceeded the 50 mg NO 3 -/l limit established for waters intended for human consumption and 33% exceeded the control range 25-50 mg NO 3 -/l. There were significant differences between water samples collected during the irrigation period, as a consequence of leaching evapoconcentrated salts and the good quality of the water used for irrigation. Concerning spatial distribution, water quality in the aquifer is related to the quality of groundwater flow, drainage from surface basin, seepage from irrigation canals, subsurface salt dissolution and leaching of nitrogen fertilizers. Nitrate is the main environmental problem, requiring further studies to evaluate alternatives to minimize nitrate pollution.

Ranada M.F.,University of Zaragoza
Journal of Physics A: Mathematical and Theoretical | Year: 2013

The higher order superintegrability of separable potentials is studied. It is proved that these potentials possess (in addition to the two quadratic integrals) a third integral of higher order in the momenta that can be obtained as the product of powers of two particular rather simple complex functions. Some systems related to the harmonic oscillator, such as the generalized SW system and the TTW system, were studied in previous papers; now a similar analysis is presented for superintegrable systems related to the Kepler problem. In this way, a new proof of the superintegrability of the Post-Winternitz system is presented and the explicit expression for the integral is obtained. Finally, the relations between the superintegrable systems with quadratic constants of motion (separable in several different coordinate systems) and the superintegrable systems with higher order constants of motion are analyzed. © 2013 IOP Publishing Ltd.

Gil J.J.,University of Zaragoza
Applied Optics | Year: 2016

While any 2D mixed state of polarization of light can be represented by a combination of a pure state and a fully random state, any Mueller matrix can be represented by a convex combination of a pure component and three additional components whose randomness is scaled in a proper and objective way. Such characteristic decomposition constitutes the appropriate framework for the characterization of the polarimetric randomness of the system represented by a given Mueller matrix and provides criteria for the optimal filtering of noise in experimental polarimetry. © 2016 Optical Society of America.

Boccaletti S.,CNR Institute for Complex Systems | Bianconi G.,Queen Mary, University of London | Criado R.,Rey Juan Carlos University | Criado R.,Technical University of Madrid | And 9 more authors.
Physics Reports | Year: 2014

In the past years, network theory has successfully characterized the interaction among the constituents of a variety of complex systems, ranging from biological to technological, and social systems. However, up until recently, attention was almost exclusively given to networks in which all components were treated on equivalent footing, while neglecting all the extra information about the temporal- or context-related properties of the interactions under study. Only in the last years, taking advantage of the enhanced resolution in real data sets, network scientists have directed their interest to the multiplex character of real-world systems, and explicitly considered the time-varying and multilayer nature of networks. We offer here a comprehensive review on both structural and dynamical organization of graphs made of diverse relationships (layers) between its constituents, and cover several relevant issues, from a full redefinition of the basic structural measures, to understanding how the multilayer nature of the network affects processes and dynamics. © 2014 Elsevier B.V.

Valles J.A.,University of Zaragoza | Galatus R.,Technical University of Cluj Napoca
IEEE Photonics Technology Letters | Year: 2013

The amplifying and filtering performance of a highly Yb/Er-codoped phosphate glass add-drop filter is numerically analyzed. The use of the microscopic statistical formalism to describe energy-transfer inter-atomic mechanisms allows determining realistic optimum parameters and working conditions. In order to optimize the device performance and achieve a significant signal power gain in both through and drop ports, in addition to a careful previous design, moderate input pump powers (> 50 mW) and comparatively high erbium concentrations (>5× 1026 m -3) are required. The optimal parameters present a strong dependence on the input pump power. This dependence confirms the necessity of considering the energy-transfer inter-atomic mechanisms for any optimization design process. © 2012 IEEE.

Pirruccio G.,FOM Institute for Atomic and Molecular Physics | Martin Moreno L.,University of Zaragoza | Lozano G.,FOM Institute for Atomic and Molecular Physics | Gomez Rivas J.,TU Eindhoven
ACS Nano | Year: 2013

We experimentally demonstrate a broadband enhancement of the light absorption in graphene over the whole visible spectrum. This enhanced absorption is obtained in a multilayer structure by using an Attenuated Total Reflectance (ATR) configuration and it is explained in terms of coherent absorption arising from interference and dissipation. The interference mechanism leading to the phenomenon of coherent absorption allows for its precise control by varying the refractive index and/or thickness of the medium surrounding the graphene. © 2013 American Chemical Society.

Kleftogiannis I.,University of Ioannina | Amanatidis I.,University of Ioannina | Gopar V.A.,University of Zaragoza
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

Conductance fluctuations produced by the presence of disorder in zigzag and armchair graphene nanoribbons are studied. We show that quantum transport in zigzag nanoribbons takes place via edge states which are exponentially localized, as in the standard Anderson localization problem, whereas for armchair nanoribbons the symmetry of the graphene sublattices produces anomalous localization, or delocalization. We show that these two different electron localizations lead to significant differences of the conductance statistics between zigzag and armchair nanoribbons. In particular, armchair nanoribbons show nonconventional large conductance fluctuations relative to those of Anderson-localized electrons. We calculate analytically the complete distribution of conductances for both types of ribbons. Without free fitting parameters, we verify our theoretical results by performing numerical simulations of disordered zigzag and armchair nanoribbons of experimentally achievable lengths and widths. © 2013 American Physical Society.

Gil J.J.,University of Zaragoza
Journal of Modern Optics | Year: 2016

The absolute values of the three degrees of mutual coherence between the analytic signals representing the components of the electric field of a given three-dimensional (3D) polarization state are relative quantities that depend on the laboratory reference frame considered. The extremal values for the said absolute values are determined and analyzed. The reduction to the well-known conventional 2D case is retrieved in a natural way. © 2015 Taylor & Francis.

Aguado M.,Max Planck Institute of Quantum Optics | Asorey M.,University of Zaragoza
Nuclear Physics B | Year: 2011

The θ dependence of the vacuum energy density in CPN-1 models is re-analysed in the semiclassical approach, the 1/N expansion and arguments based on the nodal structure of vacuum wavefunctionals. The 1/N expansion is shown not to be in contradiction with instanton physics at finite (spacetime) volume V. The interplay of large volume V and large N parameter gives rise to two regimes with different θ dependence, one behaving as a dilute instanton gas and the other dominated by the traditional large N picture, where instantons reappear as resonances of the one-loop effective action, even in the absence of regular instantonic solutions. The realms of the two regimes are given in terms of the mass gap m by m2V«N and m2V«N, respectively. The small volume regime m2V«N is relevant for physical effects associated to the physics of the boundary, like the leading rôle of edge states in the quantum Hall effect, which, however, do not play any rôle in the thermodynamic limit at large N. Depending on the order in which the limits N→∞ and V→∞ are taken, two different theories are obtained; this is the hallmark of a phase transition at 1/N=0. © 2010 Elsevier B.V.

Estrada-Pena A.,University of Zaragoza | Gray J.S.,University College Dublin | Kahl O.,Tick radar GmbH | Lane R.S.,University of California at Berkeley | Nijhof A.M.,Free University of Berlin
Frontiers in Cellular and Infection Microbiology | Year: 2013

Interest in tick-transmitted pathogens has experienced an upsurge in the past few decades. Routine application of tools for the detection of fragments of foreign DNA in ticks, together with a high degree of interest in the quantification of disease risk for humans, has led to a marked increase in the number of reports on the eco-epidemiology of tick-borne diseases. However, procedural errors continue to accumulate in the scientific literature, resulting in misleading information. For example, unreliable identification of ticks and pathogens, erroneous interpretations of short-term field studies, and the hasty acceptance of some tick species as vectors have led to ambiguities regarding the vector role of these arthropods. In this review, we focus on the ecological features driving the life cycle of ticks and the resulting effects on the eco-epidemiology of tick-transmitted pathogens. We review the factors affecting field collections of ticks, and we describe the biologically and ecologically appropriate procedures for describing tick host-seeking activity and its correlation with environmental traits. We detail the climatic variables that have biological importance on ticks and explain how they should be properly measured and analyzed. We also provide evidence to critically reject the use of some environmental traits that are being increasingly reported as the drivers of the behavior of ticks. With the aim of standardization, we propose unambiguous definitions of the status of hosts and ticks regarding their ability to maintain and spread a given pathogen. We also describe laboratory procedures and standards for evaluating the vectorial capacity of a tick or the reservoir role of a host. This approach should provide a coherent framework for the reporting of research findings concerning ticks and tick-borne diseases. © 2013 Estrada-Peña, Gray, Kahl, Lane and Nijhof.

Bobillo F.,University of Zaragoza | Delgado M.,University of Granada | Gomez-Romero J.,Charles III University of Madrid
Expert Systems with Applications | Year: 2012

Today, there is a growing interest in the development of knowledge representations able to deal with uncertainty, which is a very common requirement in real world applications. Despite the undisputed success of ontologies, classical ontologies are not suitable to deal with uncertainty and, consequently, several extensions with fuzzy logic and rough logic, among other formalisms, have been proposed. In this article we describe DeLorean 2, the first ontology reasoner that supports fuzzy extensions of the standard languages OWL and OWL 2. In a strict sense, DeLorean is not a reasoner but a translator from fuzzy rough ontology languages (GZSROIQ(D)) into classical ontology languages (SROIQ(D)). This allows using classical (widely available) Description Logic inference engines to reason with the representation resulting from the transformation. We describe the main features of the application: evolution, functionality, architecture, graphical interface, input language, and implementation details. © 2011 Elsevier Ltd. All rights reserved.

Barbana C.,University of Zaragoza | El-Omri A.,University of Tsukuba
Food and Bioprocess Technology | Year: 2012

The rheological properties of tomato concentrates produced by hot and cold break have been extensively studied by many authors. Only a few studies, however, focus specifically with the rheology of reconstituted concentrates from tomato powders. In this study, the rheological properties of reconstituted tomato concentrate from lyophilized freeze-dried tomato juice were evaluated using rotational viscometer at temperatures 20 °C, 30 °C, 40 °C, 50 °C, and 60 °C and at concentrations of 9. 7%, 12. 9%, 20. 5%, and 26. 8% total soluble solids. Using power law model, both flow behavior index (n) and consistency coefficient (k) were determined. The calculated values of flow behavior index (n) were less than unity (0. 03-0. 28) at all temperatures and concentrations indicating the shear-thinning characteristic of the concentrate. The effect of temperature and concentration on the consistency coefficient (k) was studied. Positive correlation between k in the range of 1. 57 and 38. 33 Pa s n and inverse absolute temperature (1/T) has been shown by Arrhenius model. Additionally, linear correlation between consistency coefficient (k) and concentration (C) was determined. The activation energies were found in the range of 3. 63 and 7. 36 kJ/mol K depending on concentration. The results of this study might be useful to improve the design of processing operations dealing with tomato powder reconstitution. © 2009 Springer Science + Business Media, LLC.

De Haan L.T.,TU Eindhoven | Sanchez-Somolinos C.,University of Zaragoza | Bastiaansen C.M.W.,TU Eindhoven | Bastiaansen C.M.W.,Queen Mary, University of London | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2012

Rise or fall: Complex-structured freestanding polymer films with molecular order in three dimensions were prepared through photoalignment of polymerizable liquid crystals. The resulting films deform into cone and saddle shapes upon heating. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zheng Y.-Z.,University of Manchester | Evangelisti M.,University of Zaragoza | Winpenny R.E.P.,University of Manchester
Angewandte Chemie - International Edition | Year: 2011

(Figure Presented) Cool stuff: The usage of phosphonates has led to formation of a family of 3d-4f heterometallic cages with a Wells-Dawson-like structure (see picture; Gd, Dy, or Y purple; Ni cyan; P green; O orange; C gray). Magnetic studies show ferromagnetic interactions within the oxocentered nickel triangle and huge entropy change in the Gd analogue, which, in principle, can be used as an ultralow-temperature coolant. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA.

Resano H.,University of Zaragoza
Food Policy | Year: 2012

Using dry-cured ham as an anchor product, consumers' preferences for EU Quality Certification schemes, region of origin and price have been investigated with conjoint analysis. In order to achieve this aim, a mixed rank-ordered logit which allows for the investigation of heterogeneous preferences and their sources has been estimated. In particular, we have analysed to what extent consumers' socio-demographic traits affect their price-sensitiveness and whether consumers' sensory (hedonic) valuations and attitudes towards ham with a Protected Designation of Origin (PDO) affect the preferences for specific attributes. Results show that consumers with a low-medium age and income are more price sensitive. Consumers more inclined sensorially towards the regional specialty (with or without PDO) are more likely to purchase this product, and consumers with a more favourable attitude towards PDO ham are also more prone to purchase cured ham with quality certification. Findings also suggest that although the PDO scheme attracts a segment of consumers, the origin by itself is still a more powerful signal of quality, and more specifically the region of origin. © 2012 Elsevier Ltd.

Cucinotta G.,University of Florence | Perfetti M.,University of Florence | Luzon J.,University of Zaragoza | Luzon J.,Centro Universitario Of La Defensa | And 6 more authors.
Angewandte Chemie - International Edition | Year: 2012

Magnetic moments: The orientation of the title single-molecule magnet was investigated by magnetic single crystal and luminescence characterization, supported by ab initio calculations, and was found to be governed by the position of the hydrogen atoms of the apical water molecules. This finding suggests that simple magneto-structural correlations can give misleading clues for research in molecular magnetism as well as in the design of MRI contrast agents. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enriquez J.A.,University of Zaragoza
International Journal of Biochemistry and Cell Biology | Year: 2015

Mitochondria are critical metabolic hubs in which catabolic and anabolic cellular processes converge and are integrated. To perform their function, mitochondria also need to respond to signals that monitor their function and send continuous feedback to the nucleus and other organelles to trigger the required expression programs (for example, stabilization of hypoxia-inducible factor 1 - α). Unsurprisingly, mitochondrial dysfunction results in wide range of disorders. Understanding how cells adapt to changes in mitochondrial function is critical for the evaluation of mitochondrial disorders and the development of potential treatments. Each type of mitochondrial dysfunction results in a unique transcriptional response. Here we review the role of nuclear-encoded factors in the response to changes in mitochondrial function and discuss their relevance to metabolic homeostasis, outlining the diverse and complex ways in which nuclei adapt to maintain mitochondrial homeostasis. This article is part of a Directed Issue entitled: Energy Metabolism Disorders and Therapies. © 2015 Elsevier Ltd. All rights reserved.

Marques-Lopez E.,University of Zaragoza | Christmann M.,TU Dortmund
Angewandte Chemie - International Edition | Year: 2012

Simple, but effective: The asymmetric heterodimerization of two different ketenes (see scheme) has been developed 65 years after the first seminal studies on ketene dimerization. The key to sufficiently suppressing the competing homodimerization of the monosubstituted ketene donor (shown in blue) is its slow addition to the disubstituted acceptor (shown in red). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

San Jose I.,Instituto Aragones Of Estadistica | Gil J.J.,University of Zaragoza
Optics Communications | Year: 2011

A proper set of indices characterizing the polarimetric purity of light and material media is defined from the eigenvalues of the corresponding coherency matrix. A simple and generalizable relation of these indices with the current parameter characterizing the global purity is obtained. A general definition for systems characterized by n × n positive semidefinite Hermitian matrices is introduced in terms of the corresponding eigenvalues and diagonal Gell-Mann matrices. The set of n - 1 indices of purity has a nested structure and provides complete information about the statistical purity of the system. © 2010 Elsevier B.V. All rights reserved.

Rodenas T.,Technical University of Delft | Van Dalen M.,Technical University of Delft | Garcia-Perez E.,Technical University of Delft | Serra-Crespo P.,Technical University of Delft | And 3 more authors.
Advanced Functional Materials | Year: 2014

Mixed matrix membranes (MMMs) composed of metal organic framework (MOF) fillers embedded in a polymeric matrix represent a promising alternative for CO2 removal from natural gas and biogas. Here, MMMs based on NH 2-MIL-53(Al) MOF and polyimide are successfully synthesized with MOF loadings up to 25 wt% and different thicknesses. At 308 K and ΔP = 3 bar, the incorporation of the MOF filler enhances CO2 permeability with respect to membranes based on the neat polymer, while preserving the relatively high separation factor. The rate of solvent evaporation after membrane casting proves key for the final configuration and dispersion of the MOF in the membrane. Fast solvent removal favours the contraction of the MOF structure to its narrow pore framework configuration, resulting in enhanced separation factor and, particularly, CO2 permeability. The study reveals an excellent filler-polymer contact, with ca. 0.11% void volume fraction, for membranes based on the amino-functionalized MOF, even at high filler loadings (25 wt%). By providing precise and quantitative insight into key structural features at the nanoscale range, the approach provides feedback to the membrane casting process and therefore it represents an important advancement towards the rational design of mixed matrix membranes with enhanced structural features and separation performance. Mixed-matrix membranes composed of the flexible NH 2-MIL-53(Al) metal-organic framework (MOF) embedded in polyimide represent a promising alternative for CO2 removal from natural gas and biogas. Quantitative focused ion beam scanning electron microscopy (FIB-SEM) tomography evidences an excellent filler-polymer contact. The loading of MOF crystals and its framework configuration, which can be adjusted during membrane casting, are key parameters for the gas separation performance. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Boya L.J.,University of Zaragoza
Physics of Atomic Nuclei | Year: 2010

We address the problem of the reasons for the existence of 12 symmetric spaces with the exceptional Lie groups. The 1 + 2 cases for G2 and F4, respectively, are easily explained from the octonionic nature of these groups. The 4 + 3 + 2 cases on the E6,7,8 series require the magic square of Freudenthal and, for the split case, an appeal to the supergravity chain in 5, 4, and 3 space-time dimensions. © 2010 Pleiades Publishing, Ltd.

Silva M.,University of Zaragoza
Nonlinear Analysis: Hybrid Systems | Year: 2016

Discrete Event Systems (DES) theory and engineering are mainly driven by needs that arise in many different human-made systems (manufacturing, communications, logistics, workflow management, traffic, etc.). With the accelerated increase in the complexity and size of new technological constructions, the state explosion problem in DES analysis and synthesis becomes more and more acute.Two traditional conceptual and complementary ways of dealing with the computational complexities in the Petri nets (PN) framework are structure theory (that investigates the relationship between the behavior of a net system and its structure) and fluid relaxations, here leading to particular classes of hybrid systems. In the second case, the expected computational gains for analysis and synthesis problems are usually achieved at the expense of the fidelity or accuracy of the relaxed model. This invited overview will mainly focus on the second strategy, nevertheless always interspersed with basic structural concepts and methods. Using an example-driven approach, starting with a DES "view of the system", the legitimization and improvement of fluidization process, the aggregation of local states by symmetries and the decolorization of models will be briefly addressed, together with reflections about the analysis of the new models obtained.As the linearization of a continuous dynamical system, the fluidization of a DES is a relaxation that has to be used with care, depending on the problem at hand. This abstraction is here considered from two complementary perspectives: at logical and at performance levels, both for untimed and timed PNs. On the one hand, the expressive power of timed fluid PNs under infinite server semantics is such that the simulation of Turing machines is possible. From a complementary perspective, the expression of modeling capabilities such as non-monotonicities and bifurcations may also be revealed for steady-state behaviors. Symmetries (more generally, lumping) seek to group together "equivalent" behaviors and decolorization seeks to abstract identities, in order to create new collectivities of processes and resources. The synergy between symmetry-decolorization state-aggregation approaches and fluid relaxations is highlighted. In fact, the first approaches not only reduce the state space, but also "produce" populations, thus proceed upgrading the applicability of fluidization. Opening the window, related issues such as control, optimization, observation or diagnosis are briefly pointed out. For conciseness, this work is limited to fully fluid (or continuous) PN models and their relationships with the corresponding discrete systems. © 2016 Elsevier Ltd.

Kuhbeck D.,University of Regensburg | Saidulu G.,Indian Institute of Chemical Technology | Reddy K.R.,Indian Institute of Chemical Technology | Diaz D.D.,University of Regensburg | Diaz D.D.,University of Zaragoza
Green Chemistry | Year: 2012

The effectiveness of neutral pH chitosan hydrogel beads (CSHB) as a green organocatalyst for a variety of C-C bond forming reactions (i.e. aldol reaction, Knoevenagel condensation, nitroaldol (Henry) reaction, Michael addition) has been comprehensively evaluated. Reaction rates, conversions and selectivities were studied as a function of a series of input variables including size, pH and reactive surface area of the beads, catalyst loading, temperature, molecular weight of the biopolymer, concentration, solvent system and molar ratio of reactants. Moreover, the catalytic biohydrogel beads were characterized by a variety of techniques including, among others, SEM, FT-IR, TGA and DSC. © 2012 The Royal Society of Chemistry.

Balcaen L.,Ghent University | Bolea-Fernandez E.,Ghent University | Resano M.,University of Zaragoza | Vanhaecke F.,Ghent University
Analytica Chimica Acta | Year: 2015

This paper is intended as a tutorial review on the use of inductively coupled plasma - tandem mass spectrometry (ICP-MS/MS) for the interference-free quantitative determination and isotope ratio analysis of metals and metalloids in different sample types. Attention is devoted both to the instrumentation and to some specific tools and procedures available for advanced method development. Next to the more typical reaction gases, e.g., H2, O2 and NH3, also the use of promising alternative gases, such as CH3F, is covered, and the possible reaction pathways with those reactive gases are discussed. A variety of published applications relying on the use of ICP-MS/MS are described, to illustrate the added value of tandem mass spectrometry in (ultra)trace analysis. © 2015 Elsevier B.V.

Lanas A.,University of Zaragoza
American Journal of Gastroenterology | Year: 2010

Although the incidence of peptic ulcer bleeding (PUB) has decreased, mortality has remained constant despite the advances in endoscopic and pharmacological therapies. Recent data indicate that most PUB-linked deaths are not direct sequelae of the bleeding ulcer itself. Instead, mortality derives from multi-organ failure, cardiopulmonary conditions, or terminal malignancy, suggesting that improving treatments for the bleeding ulcer may impact mortality by very little. Recognizing this possibility is paramount for the implementation of strategies that provide supportive care and prevent complications and key-organ failure, as well as treat the ulcer. Identifying non-gastrointestinal (GI) risk factors for poor outcomes and a multidisciplinary approach for high-risk patients should help to affect this hard outcome. © 2010 by the American College of Gastroenterology.

Palacio F.,University of Zaragoza
Chemical Communications | Year: 2014

I discuss here the contribution from J. S. Miller and co-workers concerning the discovery of ferromagnetism in an organometallic compound. The important peculiarities around this discovery, that the moments from p-electrons participate in magnetic ordering, strongly contributed to open the area of molecule-based magnetic materials as a new area of research. © The Partner Organisations 2014.

Maraver D.,Research Center for Energy Resources and Consumption | Quoilin S.,University of Liege | Royo J.,University of Zaragoza
Entropy | Year: 2014

This work is focused on the thermodynamic optimization of Organic Rankine Cycles (ORCs), coupled with absorption or adsorption cooling units, for combined cooling heating and power (CCHP) generation from biomass combustion. Results were obtained by modelling with the main aim of providing optimization guidelines for the operating conditions of these types of systems, specifically the subcritical or transcritical ORC, when integrated in a CCHP system to supply typical heating and cooling demands in the tertiary sector. The thermodynamic approach was complemented, to avoid its possible limitations, by the technological constraints of the expander, the heat exchangers and the pump of the ORC. The working fluids considered are: n-pentane, n-heptane, octamethyltrisiloxane, toluene and dodecamethylcyclohexasiloxane. In addition, the energy and environmental performance of the different optimal CCHP plants was investigated. The optimal plant from the energy and environmental point of view is the one integrated by a toluene recuperative ORC, although it is limited to a development with a turbine type expander. Also, the trigeneration plant could be developed in an energy and environmental efficient way with an n-pentane recuperative ORC and a volumetric type expander. © 2014 by the authors; licensee MDPI, Basel, Switzerland.

Cuesta J.A.,Charles III University of Madrid | Cuesta J.A.,University of Zaragoza | Quintero N.R.,University of Seville | Alvarez-Nodarse R.,University of Seville
Physical Review X | Year: 2014

Ratchets are devices that are able to rectify an otherwise oscillatory behavior by exploiting an asymmetry of the system. In rocking ratchets, the asymmetry is induced through a proper choice of external forces and modulations of nonlinear symmetric potentials. The ratchet currents thus obtained in systems as different as semiconductors, Josephson junctions, optical lattices, or ferrofluids show a set of universal features. A satisfactory explanation for them has challenged theorists for decades, and so far, we still lack a general theory of this phenomenon. Here, we provide such a theory by exploring-through functional analysis-the constraints that the simple assumption of time-shift invariance of the ratchet current imposes on its dependence on the external drivings. Because the derivation is based on so general a principle, the resulting expression is valid irrespective of the details and the nature of the physical systems to which it is applied, and of whether they are classical, quantum, or stochastic. The theory also explains deviations observed from universality under special conditions and allows us to make predictions of phenomena not yet observed in any experiment or simulation.

Zhang Z.,CAS Institute of Geology and Geophysics | Xu T.,CAS Institute of Geology and Geophysics | Zhao B.,CAS Institute of Geology and Geophysics | Badal J.,University of Zaragoza
Gondwana Research | Year: 2013

The South China continent has a Mesozoic intraplate orogeny in its interior and an oceanward younging in postorogenic magmatic activity. In order to determine the constraints afforded by deep structure on the formation of these characteristics, we reevaluate the distribution of crustal velocities and wide-angle seismic reflections in a 400. km-long wide-angle seismic profile between Lianxian, near Hunan Province, and Gangkou Island, near Guangzhou City, South China. The results demonstrate that to the east of the Chenzhou-Linwu Fault (CLF) (the southern segment of the Jiangshan-Shaoxing Fault), the thickness and average P-wave velocity both of the sedimentary layer and the crystalline basement display abrupt lateral variations, in contrast to layering to the west of the fault. This suggests that the deformation is well developed in the whole of the crust beneath the Cathaysia block, in agreement with seismic evidence on the eastwards migration of the orogeny and the development of a vast magmatic province. Further evidence of this phenomenon is provided in the systematic increases in seismic reflection strength from the Moho eastwards away from the boundary of the CLF, as revealed by multi-filtered (with band-pass frequency range of 1-4, 1-8, 1-12 and 1-16. Hz) wide-angle seismic images through pre-stack migration in the depth domain, and in the P-wave velocity model obtained by travel time fitting. The CLF itself penetrates with a dip angle of about 22° to the bottom of the middle part of the crust, and then penetrates with a dip angle of less than 17° in the lower crust. The systematic variation in seismic velocity, reflection strength and discrepancy of extensional factors between the crust and the lithosphere, are interpreted to be the seismic signature of the magmatic activity in the interest area, most likely caused by the intrusion of magma into the deep crust by lithospheric extension or mantle extrusion. © 2012 International Association for Gondwana Research.

Escolano C.,University of Zaragoza
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference | Year: 2011

Neurofeedback (NF) training has revealed its therapeutical effects to treat a variety of neurological and psychological disorders, and has demonstrated its feasibility to improve certain cognitive aptitudes in healthy users. Although promising results of NF training exist in recent literature, the reliability of its effects remains questioned due to a lack of deep studies examining its impact on the human electrophysiology. This paper presents a NF training aimed at improving working memory performance in healthy users by the enhancement of upper alpha band. A user-specific training was used (upper alpha was determined for each user using the individual alpha frequency) to reduce the unspecific factors of training the entire classical alpha band as traditional NF usually does. EEG assessments in active and passive open-eyes state were conducted pre/post the NF training. The EEG analyses reveal the UA enhancement during the active tasks which is independent of other frequency bands. UA was also enhanced in the passive state but independence could not be obtained in lower alpha band. Finally, significant improvement in working memory was obtained with regard to a control group.

Hargrove A.E.,University of Texas at Austin | Nieto S.,University of Zaragoza | Zhang T.,Henkel AG | Sessler J.L.,University of Texas at Austin | And 2 more authors.
Chemical Reviews | Year: 2011

The investigation of synthetic (abiotic) phosphate receptors seeks to provide improved methodologies for the detection, extraction, and transport of biologically, chemically, and environmentally important phosphates. The design of phosphate receptors is complicated by the acid-base properties of phosphate anions. In addition to the more common anion-hydrogen bond donor interactions, protonated phosphate anions can also interact with hydrogen bond acceptors. A variety of recognition interactions, such as hydrogen bonding, electrostatic interactions, van der Waals forces, π-surface interactions, shape complementarity, and metal coordination, have been employed alone or in concert to generate phosphate receptors. Many noncolored receptors have been functionalized with chromophores to produce covalent frameworks that undergo a pronounced color change when treated with an appropriate guest. Indicator displacement assay (IDA) is a competition method for the sensing of analytes.

Escuer A.,University of Barcelona | Esteban J.,University of Barcelona | Roubeau O.,University of Zaragoza
Inorganic Chemistry | Year: 2011

In the present work, novel coordination possibilities for the system dapdoH2/NiII (dapdoH2 = 2,6-diacetylpyridine- dioxime) have been explored. Depending on the starting reagents and solution conditions, several clusters with nuclearities ranging from Ni5 to Ni10 were achieved and structurally characterized, namely, [Ni 5(R-COO)2(dapdo)2(dapdoH)2(N(CN) 2)2(MeOH)2] in which R-COO- = benzoate (1) or 3-chlorobenzoate (2), [Ni8(dapdo)4(NO 3)4(OH)4(MeOH)4] (3), and [Ni 10(dapdo)8(N(CN)2)2(MeO)(MeOH)] (NO3) (4). For the first time, pentadentate coordination for the dapdo2- ligand has been established. All compounds show a combination of square-planar and octahedrally coordinated nickel atoms. According to the Ni2(sp)Ni3(Oh) (1 and 2), Ni4(sp)Ni 4(Oh) (3), and Ni4(sp)Ni6(Oh) (4) environments, these systems magnetically behave as trimer, tetramer, and hexanuclear clusters, respectively. dc magnetic measurements in the 2-300 K range of temperature reveal antiferromagnetic coupling for all compounds, and the correlation of the superexchange interaction with the torsion angles involving the oximato bridges is experimentally confirmed. © 2011 American Chemical Society.

Walters A.J.C.,University of Amsterdam | Troeppner O.,Friedrich - Alexander - University, Erlangen - Nuremberg | Ivanovic-Burmazovic I.,Friedrich - Alexander - University, Erlangen - Nuremberg | Tejel C.,University of Zaragoza | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2012

Breath-taking activation: Stereoregular carbene polymerization proceeds via cationic [(allyl)Rh III-polymeryl] + species. These are most efficiently generated by oxygenation of the [(diene)Rh I] precatalysts, which involves an unusual rearrangement of 2-rhodaoxetane intermediates. This discovery gives detailed insight in the reaction mechanism. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Strasdat H.,Imperial College London | Montiel J.M.M.,University of Zaragoza | Davison A.J.,Imperial College London
Image and Vision Computing | Year: 2012

While the most accurate solution to off-line structure from motion (SFM) problems is undoubtedly to extract as much correspondence information as possible and perform batch optimisation, sequential methods suitable for live video streams must approximate this to fit within fixed computational bounds. Two quite different approaches to real-time SFM - also called visual SLAM (simultaneous localisation and mapping) - have proven successful, but they sparsify the problem in different ways. Filtering methods marginalise out past poses and summarise the information gained over time with a probability distribution. Keyframe methods retain the optimisation approach of global bundle adjustment, but computationally must select only a small number of past frames to process. In this paper we perform a rigorous analysis of the relative advantages of filtering and sparse bundle adjustment for sequential visual SLAM. In a series of Monte Carlo experiments we investigate the accuracy and cost of visual SLAM. We measure accuracy in terms of entropy reduction as well as root mean square error (RMSE), and analyse the efficiency of bundle adjustment versus filtering using combined cost/accuracy measures. In our analysis, we consider both SLAM using a stereo rig and monocular SLAM as well as various different scenes and motion patterns. For all these scenarios, we conclude that keyframe bundle adjustment outperforms filtering, since it gives the most accuracy per unit of computing time. © 2012 Elsevier B.V. All rights reserved.

The combination of nonadiabatic Ehrenfest-path molecular dynamics (EMD) based on time-dependent density functional theory (TDDFT) and quantum optimal control formalism (QOCT) was used to optimize the shape of ultra-short laser pulses to achieve photodissociation of a hydrogen molecule and the trihydrogen cation H3 +. This work completes a previous one [A. Castro, ChemPhysChem, 2013, 14, 1488-1495], in which the same objective was achieved by demonstrating the combination of QOCT and TDDFT for many-electron systems on static nuclear potentials. The optimization model, therefore, did not include the nuclear movement and the obtained dissociation mechanism could only be sequential: fast laser-assisted electronic excitation to nonbonding states (during which the nuclei are considered to be static), followed by field-free dissociation. Here, in contrast, the optimization was performed with the QOCT constructed on top of the full dynamic model comprised of both electrons and nuclei, as described within EMD based on TDDFT. This is the first numerical demonstration of an optimal control formalism for a hybrid quantum-classical model, that is, a molecular dynamics method. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cimini G.,Charles III University of Madrid | Sanchez A.,University of Zaragoza
Journal of the Royal Society Interface | Year: 2014

Cooperative behaviour lies at the very basis of human societies, yet its evolutionary origin remains a key unsolved puzzle. Whereas reciprocity or conditional cooperation is one of the most prominent mechanisms proposed to explain the emergence of cooperation in social dilemmas, recent experimental findings on networked Prisoner's Dilemma games suggest that conditional cooperation also depends on the previous action of the player - namely on the 'mood' in which the player is currently in. Roughly, a majority of people behave as conditional cooperators if they cooperated in the past, whereas they ignore the context and free ride with high probability if they did not. However, the ultimate origin of this behaviour represents a conundrum itself. Here, we aim specifically to provide an evolutionary explanation of moody conditional cooperation (MCC). To this end, we perform an extensive analysis of different evolutionary dynamics for players' behavioural traits - ranging from standard processes used in game theory based on pay-off comparison to others that include non-economic or social factors. Our results show that only a dynamic built upon reinforcement learning is able to give rise to evolutionarily stable MCC, and at the end to reproduce the human behaviours observed in the experiments. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Munoz A.,University of Zaragoza
Computer Graphics Forum | Year: 2014

Rendering participating media is still a challenging and time consuming task. In such media light interacts at every differential point of its path. Several rendering algorithms are based on ray marching: dividing the path of light into segments and calculating interactions at each of them. In this work, we revisit and analyze ray marching both as a quadrature integrator and as an initial value problem solver, and apply higher order adaptive solvers that ensure several interesting properties, such as faster convergence, adaptiveness to the mathematical definition of light transport and robustness to singularities. We compare several numerical methods, including standard ray marching and Monte Carlo integration, and illustrate the benefits of different solvers for a variety of scenes. Any participating media rendering algorithm that is based on ray marching may benefit from the application of our approach by reducing the number of needed samples (and therefore, rendering time) and increasing accuracy. © 2014 The Authors. Computer Graphics Forum © 2014 The Eurographics Association and John Wiley & Sons Ltd. Published by John Wiley & Sons Ltd.

Lippert B.,TU Dortmund | Sanz Miguel P.J.,University of Zaragoza
Coordination Chemistry Reviews | Year: 2016

This article reviews discrete complexes of platinum in its common oxidation states +II, +III, and +IV with aqua, hydroxido, oxido, and peroxido ligands, which at some point had been considered unstable and difficult to isolate because of an incompatibility between the "soft" nature of the metal and the "hard" nature of the O-ligands. The sheer number of structurally fully characterized examples contradicts this view, and numerous studies confirm their existence in solution and reveal at the same time distinct reactivity patterns. These make Pt complexes with O-donor atoms interesting candidates for medicinally important Pt antitumor drugs as well as catalytically relevant species. © 2016 Elsevier B.V.

Martinez De Morentin J.I.,University of the Basque Country | Cortes A.,University of Zaragoza | Medrano C.,University of the Basque Country | Apodaca P.,University of the Basque Country
Computers and Education | Year: 2014

The aim of this research project was to analyze the relationship between Internet use and parental mediation in a cross-cultural sample group. It also aimed to explore the relationship between parental mediation in Internet use and television viewing. The sample group comprised 1238 adolescents aged between 14 and 19, from eight different cultural contexts. The television viewing habits questionnaire (CH-TV.02) was used to analyze the following indicators: reason for use and hours spent on the Internet, parental mediation in Internet use and parental mediation in television viewing. The data were collected both by means of an online platform and in person. The results show a moderate use of the Internet with context-based variations, although the communicative function was predominant in all cultural contexts studied. Although significant differences were found between the different contexts, they were moderate in nature and should be interpreted with caution, given the size of the sample. In relation to parental mediation in Internet use, an exploratory factorial analysis found three types of mediation, with restrictive mediation and co-viewing being particularly relevant. As regards the profiles found, a Cluster analysis identified four profiles in the group of young people studied: instructive, inhibited, co-viewing and restrictive, with the inhibited profile being the one most frequently perceived by adolescents, followed by co-viewing, with significant differences being observed between cultures. Differences were observed in parental mediation in Internet use and television viewing in accordance with the medium in question and the context, a finding which may indicate that parents find it harder to engage in instructive mediation and co-viewing in relation to the Internet, since it is a medium that is less ergonomic and user-friendly than television. © 2013 Elsevier Ltd. All rights reserved.

De La Escosura-Muniz A.,Biosensors | De La Escosura-Muniz A.,University of Zaragoza | Parolo C.,Biosensors | Merkoi A.,Biosensors
Materials Today | Year: 2010

Immunosensing technology is taking advantage of the lastest developments in materials science and inparticular from the nanomaterials field. Because of their unprecedented optical tunability as well as electrical and electrochemical qualities, we are seeing significant developments in the design of novel immunoassays; various conventional optical and electrical platforms which allow for future applications in several fields are being used. Properties of nanoparticles such as light absorption and dispersion are bringing interesting immunosensing alternatives. Nanoparticles are improving the sensitivity of existing techniques used for protein detection in immunoassays based on Surface Plasmon Resonance, Quartz Crystal Microbalance, Fluorescence spectroscopy etc. Electrochemical techniques are also taking advantage of electrical properties of nanoparticles. Redox properties of metal based nanoparticles, surface impedance change and conductance changes once nanoparticles are present as labelling tags or modifiers of transducer surfaces are also improving the technology. In most of the examples nanoparticle based biosensing systems are being offered as excellent screening and superior alternatives to existing conventional strategies/assays with interest for fields in clinical analysis, food quality, safety and security. © 2010 Elsevier Ltd.

Gopar V.A.,University of Zaragoza | Molina R.A.,CSIC - Institute for the Structure of Matter
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

We calculate the entire distribution of the conductance P (G) of a one-dimensional disordered system-quantum wire-subject to a time-dependent field. Our calculations are based on Floquet theory and a scaling approach to localization. Effects of the applied ac field on the conductance statistics can be strong and in some cases dramatic, as in the high-frequency regime where the conductance distribution shows a sharp cutoff. In this frequency regime, the conductance is written as a product of a frequency-dependent term and a field-independent term, the latter containing the information on the disorder in the wire. We thus use the solution of the Mel'nikov equation for time-independent transport to calculate P (G) at any degree of disorder. At lower frequencies, it is found that the conductance distribution and the correlations of the transmission Floquet modes are described by a solution of the Dorokhov-Mello-Pereyra-Kumar equation with an effective number of channels. In the regime of strong localization, induced by the disorder or the ac field, P (G) is a log-normal distribution. Our theoretical results are verified numerically using a single-band Anderson Hamiltonian. © 2010 The American Physical Society.

Fernandez J.F.,University of Zaragoza | Fernandez J.F.,University of Granada
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

By tempered Monte Carlo simulations, an Almeida-Thouless (AT) phase-boundary line in site-diluted Ising spin systems is searched for. Spins interact only through dipolar fields and occupy a small fraction of lattice sites. The spin-glass susceptibility of these systems and of the Sherrington-Kirkpatrick model are compared. The correlation length as a function of system size and temperature is also studied. The results obtained are contrary to the existence of an AT line. © 2010 The American Physical Society.

Verbunt P.P.C.,TU Eindhoven | Sanchez-Somolinos C.,University of Zaragoza | Broer D.J.,TU Eindhoven | Debije M.G.,TU Eindhoven
Optics Express | Year: 2013

In this paper we develop a model to describe the emission profile from randomly oriented dichroic dye molecules in a luminescent solar concentrator (LSC) waveguide as a function of incoming light direction. The resulting emission is non-isotropic, in contradiction to what is used in almost all previous simulations on the performance of LSCs, and helps explain the large surface losses measured in these devices. To achieve more precise LSC performance simulations we suggest that the dichroic nature of the dyes must be included in the future modeling efforts. © 2013 Optical Society of America.

Perez-Lopez F.R.,University of Zaragoza | Chedraui P.,Catholic University of Santiago de Guayaquil | Fernandez-Alonso A.M.,Hospital Torrecardenas
Maturitas | Year: 2011

Background: Low serum 25-hydroxyvitamin D (25[OH]D) levels are common and may be associated with morbidity and mortality (and indeed with frailty more generally). This association is not restricted to the links between vitamin D and calcium and bone metabolism. Objective: To review the influences of vitamin D on the aging process other than those related to bone and calcium. Its effect on mortality is also assessed. Methods: The PubMed database was searched for English-language articles relating to vitamin D, using the following MeSH terms: vitamin D, mortality, cardiovascular diseases, and frailty. In addition, searches were carried out with Google. Results: Although some of the reported results have proved controversial, overall the evidence seems to support an association between low serum 25[OH]D levels and mortality rates (all-cause and cardiovascular). Frailty is a condition frequently associated with low serum 25[OH]D levels. Conclusion: The aging process and mortality are associated with low vitamin D levels. Prospective controlled trials are warranted to determine whether vitamin D supplements can increase longevity and reduce the incidence of certain conditions. © 2011 Elsevier Ireland Ltd. All rights reserved.

Bolea R.,University of Zaragoza
BMC genomics | Year: 2014

Prion diseases are characterized by the accumulation of the pathogenic PrPSc protein, mainly in the brain and the lymphoreticular system. Although prions multiply/accumulate in the lymph nodes without any detectable pathology, transcriptional changes in this tissue may reflect biological processes that contribute to the molecular pathogenesis of prion diseases. Little is known about the molecular processes that occur in the lymphoreticular system in early and late stages of prion disease. We performed a microarray-based study to identify genes that are differentially expressed at different disease stages in the mesenteric lymph node of sheep naturally infected with scrapie. Oligo DNA microarrays were used to identify gene-expression profiles in the early/middle (preclinical) and late (clinical) stages of the disease. In the clinical stage of the disease, we detected 105 genes that were differentially expressed (≥2-fold change in expression). Of these, 43 were upregulated and 62 downregulated as compared with age-matched negative controls. Fewer genes (50) were differentially expressed in the preclinical stage of the disease. Gene Ontology enrichment analysis revealed that the differentially expressed genes were largely associated with the following terms: glycoprotein, extracellular region, disulfide bond, cell cycle and extracellular matrix. Moreover, some of the annotated genes could be grouped into 3 specific signaling pathways: focal adhesion, PPAR signaling and ECM-receptor interaction. We discuss the relationship between the observed gene expression profiles and PrPSc deposition and the potential involvement in the pathogenesis of scrapie of 7 specific differentially expressed genes whose expression levels were confirmed by real time-PCR. The present findings identify new genes that may be involved in the pathogenesis of natural scrapie infection in the lymphoreticular system, and confirm previous reports describing scrapie-induced alterations in the expression of genes involved in protein misfolding, angiogenesis and the oxidative stress response. Further studies will be necessary to determine the role of these genes in prion replication, dissemination and in the response of the organism to this disease.

Garatachea N.,University of Zaragoza | Lucia A.,European University at Madrid
Age | Year: 2013

Western populations are living longer. Ageing decline in muscle mass and strength (i.e. sarcopenia) is becoming a growing public health problem, as it contributes to the decreased capacity for independent living. It is thus important to determine those genetic factors that interact with ageing and thus modulate functional capacity and skeletal muscle phenotypes in older people. It would be also clinically relevant to identify 'unfavourable' genotypes associated with accelerated sarcopenia. In this review, we summarized published information on the potential associations between some genetic polymorphisms and muscle phenotypes in older people. A special emphasis was placed on those candidate polymorphisms that have been more extensively studied, i.e. angiotensin-converting enzyme (ACE) gene I/D, α-actinin-3 (ACTN3) R577X, and myostatin (MSTN) K153R, among others. Although previous heritability studies have indicated that there is an important genetic contribution to individual variability in muscle phenotypes among old people, published data on specific gene variants are controversial. The ACTN3 R577X polymorphism could influence muscle function in old women, yet there is controversy with regards to which allele (R or X) might play a 'favourable' role. Though more research is needed, up-to-date MSTN genotype is possibly the strongest candidate to explain variance among muscle phenotypes in the elderly. Future studies should take into account the association between muscle phenotypes in this population and complex gene-gene and gene-environment interactions. © 2011 American Aging Association.

Miralbes R.,University of Zaragoza
International Journal of Heavy Vehicle Systems | Year: 2012

The aim of this paper is the aerodynamic study of the use of Vortex Generators (VGs) in some zones of a heavy vehicle (the gap between the cab and the trailer and the rear part of the trailer) using computational fluid dynamic methodology to compare their behaviour in some zones with themselves and with the model without them, analysing the drag forces, the fuel efficiency and the aerodynamic behaviour of the vehicle, because the fuel efficiency and the economic study are essential aspects that have a high influence in heavy vehicles. Copyright © 2012 Inderscience Enterprises Ltd.

Regues D.,CSIC - Pyrenean Institute of Ecology | Nadal-Romero E.,University of Zaragoza
Catena | Year: 2013

Badlands are important in terms of sediment yield, particularly in mountain areas having subhumid and humid climatic conditions. Various studies concerning erosion and hydrological processes have demonstrated that suspended sediment transport is probably the main process in sediment export from badland areas. In the Araguás catchment (central Pyrenees) there is a statistically significant positive linear relationship between maximum discharge and the maximum suspended sediment concentration (SSC). The high frequency of hyper-concentrated fluxes of SSC (>500g·l-1) recorded at two gauging stations close to badland areas in the Pyrenees (Araguás) and the Alps (Draix) indicates that these fluxes are not uncommon, and suggests that they may transport relatively large suspended particles, especially during extreme floods. In a study involving sampling during two moderate floods (August 2006 and February 2007) in the Araguás catchment it was observed that the mean suspended sediment particle size was significantly greater during the highest SSC conditions. The results showed the great heterogeneity of particle sizes that can affect suspended sediment transport, which is usually estimated from concentration determined from turbidity values obtained using infrared devices and associated with the corresponding discharge value. Infrared turbidimeters have problems in detecting particles with a diameter (D)>0.1mm, although discharge can be evaluated with relative high accuracy. The combination of these factors suggests that the evaluation of sediment yield from badland areas using turbidity values involves significant uncertainty. If most suspended sediment is transported during moderate-high floods, which carry large quantities of suspended particles having D. >0.1. mm, then the sediment yield will be underestimated. The uncertainty can be calculated by determining the percentage and mean diameter of particles not detected, and the specific weight of the material. However, the uncertainty is not linear because of the exponential relationship between increasing diameter and the volume/mass, and consequently the error will increase with the growth in the suspended concentration. In this study the physical factors associated with uncertainty in the estimation of sediment yield were investigated, and quantitative estimates of the errors involved are provided. © 2012 Elsevier B.V.

Sostres C.,Hospital Clinico Universitario Lozano Blesa | Lanas A.,Hospital Clinico Universitario Lozano Blesa | Lanas A.,University of Zaragoza
Drugs | Year: 2011

Patients taking low-dose aspirin for cardiovascular prevention who develop an acute peptic ulcer bleeding event represent a serious challenge in clinical practice. Aspirin discontinuation is associated with increased risk of developing a new cardiovascular event, but there is little evidence on the outcomes and best management strategy in the setting of an acute ulcer bleeding event. In this clinical scenario, it is common clinical practice to interrupt aspirin treatment for various, sometimes long, periods of time. A recent study suggests that patients with bleeding ulcers who keep taking aspirin after successful endoscopic therapy followed by high-dose intravenous pantoprazole, bolus of 80 mg followed by 8mg/h for 3 days, have a small increase in the risk of rebleeding but a lower overall and cardiovascular 30-day mortality rate than those who stop taking aspirin treatment. Based on current, although limited, data, we propose that these patients should undergo early endoscopic therapy to control bleeding followed by a high-dose intravenous PPI, with early reintroduction of aspirin treatment within a 5-day window after the last dose. However, in patients taking aspirin for the primary prevention of cardiovascular events, it seems reasonable to stop aspirin treatment, reevaluate the indication and, if needed, reintroduce aspirin after the risk of ulcer rebleeding decreases, usually after hospital discharge. In the presence of an acute ulcer bleeding event soon after the placement of coronary stents, the risk of stent thrombosis with removal of antiplatelet therapy is very high. We believe that early therapeutic endoscopy and a high-dose intravenous PPI is advisable in order to maintain patients on dual antiplatelet therapy. Until more evidence becomes available, clinicians will have to rely on actual data and the use of common sense to select the best option for the patient. © 2011 Adis Data Information BV. All rights reserved.

Navarro R.,University of Zaragoza
Journal of Vision | Year: 2014

A general schematic model of the optical system of the emmetropic human eye is proposed, capable of adapting to changes with age and accommodation through adjustment of the optical surfaces and the internal gradient index structure of the lens. The specific models of the cornea and lens consist of minor generalizations of previous work by assuming them to be the sum of a biconic plus three higher order Zernike modes. The internal gradient index distribution adapts to the external shape so that the analytical expression is invariant with the changes with age and accommodation. The model also includes tips, tilts, and decentrations of the surfaces according to experimental findings. The specific parameters of these models are either constants or functions of age and/or accommodation. The model is polychromatic, and its optical performance was evaluated along the keratometric axis. Chromatic aberrations (longitudinal and transverse), astigmatism, coma, trefoil, and spherical aberration show good agreement with experimental averages. The change of these aberrations as a function of age or accommodation is also consistent with experimental findings (except for trefoil in eyes older than 50 years). This means that the average structure seems to predict the average performance. Nevertheless, the present model is too schematic to account for other higher order aberrations, such as tetrafoil, also present in real eyes. © 2014 ARVO.

Galvez Galve J.J.,University of Zaragoza
Medicina Naturista | Year: 2014

The practice of meditation, supported by scientific, and psychological therapies incorporated into third-generation studies, helps us to control and regulate our emotions. Buddhism has a wide variety of meditative techniques, helping us to calm the mind, replace destructive emotions by other healthy and be kind to ourselves.

Estrada-Pena A.,University of Zaragoza
OIE Revue Scientifique et Technique | Year: 2015

Ticks are prominent parasites and competent vectors of pathogens that affect both humans and animals. This review outlines and illustrates the main features of the morphology of ticks of the families Ixodidae and Argasidae, and summarises the basic components of their life cycles. It focuses mainly on development processes and mortality among tick populations so as to provide an overview of how they are regulated in nature and how pathogens can be transmitted under such a framework. The effects of the weather on these life cycles are reviewed. The author also examines how landscape structure and biotic factors, such as the presence and abundance of hosts, may shape the density of tick populations. The uncertainty inherent in dealing with the transmission of pathogens by ticks is highlighted; this results from the sometimes complex relationships among the vectors, the climate and the presence and density of host populations. The need to obtain reliable field estimations of such relationships before drawing conclusions about the effects of the isolated components of the system is stressed. A section is devoted to addressing the expected (and not yet totally understood) effects of trends in climate on the spread of ticks, and how these can be analysed and tracked.

Ranada M.F.,University of Zaragoza
Journal of Physics A: Mathematical and Theoretical | Year: 2012

The higher order superintegrability of systems separable in polar coordinates is studied using an approach that was previously applied for the study of the superintegrability of a generalized Smorodinsky-Winternitz system. The idea is that the additional constant of motion can be factorized as the product of powers of two particular rather simple complex functions (here denoted by M and N). This technique leads to a proof of the superintegrability of the Tremblay-Turbiner-Winternitz system and to the explicit expression of the constants of motion. A second family (related with the first one) of superintegrable systems is also studied. © 2012 IOP Publishing Ltd.

Raada M.F.,University of Zaragoza
Journal of Physics A: Mathematical and Theoretical | Year: 2012

The first part of the paper is devoted to the theory of master symmetries using the geometric formalism as an approach. It is shown that certain superintegrable systems are endowed with this property as a consequence of the existence of a family of master symmetries. In the second part, the properties of dynamical but non-Hamiltonian symmetries are studied. It is proved that the higher order superintegrability of the generalized SmorodinskyWinternitz system is a consequence of the existence of symplectic symmetries not preserving the Hamiltonian function. © 2012 IOP Publishing Ltd.

Badia-Majos A.,University of Zaragoza | Lopez C.,University of Alcala
Superconductor Science and Technology | Year: 2012

A theory for the electromagnetic response of type-II superconductors close beyond the critical state is presented. Our formulation relies on general physical principles applied to the superconductor as a thermodynamic system. Metastable equilibrium critical states, externally driven steady solutions, and transient relaxation are all described in terms of free energy and entropy production. This approach allows a consistent macroscopic statement that incorporates the intricate vortex dynamic effects, revealed in non-idealized experimental configurations. Magnetically anisotropic critical currents and flux stirring resistivities are straightforwardly included in three-dimensional scenarios. Starting from a variational form of our postulate, a numerical implementation for practical configurations is shown. In particular, several results are provided for infinite strip geometry: voltage generation in multicomponent experiments, and magnetic relaxation towards the critical state under applied field and transport current. Explicitly, we show that for a given set of external conditions, the well established critical states may be completely obtained as diffusive final profiles. © 2012 IOP Publishing Ltd.

Fdez-Gubieda M.L.,University of the Basque Country | Muela A.,University of the Basque Country | Alonso J.,University of the Basque Country | Garcia-Prieto A.,University of the Basque Country | And 3 more authors.
ACS Nano | Year: 2013

Magnetotactic bacteria biosynthesize magnetite nanoparticles of high structural and chemical purity that allow them to orientate in the geomagnetic field. In this work we have followed the process of biomineralization of these magnetite nanoparticles. We have performed a time-resolved study on magnetotactic bacteria Magnetospirillum gryphiswaldense strain MSR-1. From the combination of magnetic and structural studies by means of Fe K-edge X-ray absorption near edge structure (XANES) and high-resolution transmission electron microscopy we have identified and quantified two phases of Fe (ferrihydrite and magnetite) involved in the biomineralization process, confirming the role of ferrihydrite as the source of Fe ions for magnetite biomineralization in M. gryphiswaldense. We have distinguished two steps in the biomineralization process: the first, in which Fe is accumulated in the form of ferrihydrite, and the second, in which the magnetite is rapidly biomineralized from ferrihydrite. Finally, the XANES analysis suggests that the origin of the ferrihydrite could be at bacterial ferritin cores, characterized by a poorly crystalline structure and high phosphorus content. © 2013 American Chemical Society.

Arganda E.,University of Zaragoza | Herrero M.J.,Autonomous University of Madrid | Marcano X.,Autonomous University of Madrid | Weiland C.,Autonomous University of Madrid
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

In this paper we consider a Higgs boson with mass and other properties compatible with those of the recently discovered Higgs particle at the LHC, and explore the possibility of new Higgs leptonic decays, beyond the standard model, with the singular feature of being lepton flavor violating (LFV). We study these LFV Higgs decays, H→lkl¯m, within the context of the inverse seesaw model (ISS) and consider the most generic case where three additional pairs of massive right-handed singlet neutrinos are added to the standard model particle content. We require in addition that the input parameters of this ISS model are compatible with the present neutrino data and other constraints, like perturbativity of the neutrino Yukawa couplings. We present a full one-loop computation of the BR(H→lkl¯m) rates for the three possible channels, lkl¯m=μτ¯, eτ¯, eμ¯, and analyze in full detail the predictions as functions of the various relevant ISS parameters. We study in parallel the correlated one-loop predictions for the radiative decays, lm→lkγ, within this same ISS context, and require full compatibility of our predictions with the present experimental bounds for the three radiative decays, μ→eγ, τ→μγ, and τ→eγ. After exploring the ISS parameter space we conclude on the maximum allowed LFV Higgs decay rates within the ISS. © 2015 American Physical Society.

Prado S.,Research Center Principe Felipe | Villarroya M.,Research Center Principe Felipe | Medina M.,University of Zaragoza | Armengod M.-E.,Research Center Principe Felipe
Nucleic Acids Research | Year: 2013

MnmE is a homodimeric multi-domain GTPase involved in tRNA modification. This protein differs from Ras-like GTPases in its low affinity for guanine nucleotides and mechanism of activation, which occurs by a cis, nucleotide- and potassium-dependent dimerization of its G-domains. Moreover, MnmE requires GTP hydrolysis to be functionally active. However, how GTP hydrolysis drives tRNA modification and how the MnmE GTPase cycle is regulated remains unresolved. Here, the kinetics of the MnmE GTPase cycle was studied under single-turnover conditions using stopped- and quench-flow techniques. We found that the G-domain dissociation is the rate-limiting step of the overall reaction. Mutational analysis and fast kinetics assays revealed that GTP hydrolysis, G-domain dissociation and Pi release can be uncoupled and that G-domain dissociation is directly responsible for the 'ON' state of MnmE. Thus, MnmE provides a new paradigm of how the ON/OFF cycling of GTPases may regulate a cellular process. We also demonstrate that the MnmE GTPase cycle is negatively controlled by the reaction products GDP and Pi. This feedback mechanism may prevent inefficacious GTP hydrolysis in vivo. We propose a biological model whereby a conformational change triggered by tRNA binding is required to remove product inhibition and initiate a new GTPase/tRNA- modification cycle. © 2013 The Author(s) 2013. Published by Oxford University Press.

Bernardi S.,Centro Universitario Of La Defensa | Campos J.,University of Zaragoza
IEEE Transactions on Systems, Man, and Cybernetics Part A:Systems and Humans | Year: 2013

The time Petri net with firing frequency intervals (TPNF) is a modeling formalism used to specify system behavior under timing and frequency constraints. Efficient techniques exist to evaluate the performance of TPNF models based on the computation of bounds of performance metrics (e.g., transition throughput, place marking). In this paper, we propose a min-max problem to compute the cycle time of a transition under optimistic assumptions. That is, we are interested in computing the lower bound. We will demonstrate that such a problem is related to a maximization linear programming problem (LP-max) previously stated in the literature, to compute the throughput upper bound of the transition. The main advantage of the min-max problem compared to the LP-max is that, in addition to the optimal value, the optimal solutions provide useful feedback to the analyst on the system behavior (e.g., performance bottlenecks). We have implemented two solution algorithms, using CPLEX APIs, to solve the min-max problem, and have compared their performance using a benchmark of TPNF models, several of these being case studies. Finally, we have applied the min-max technique for the vulnerability analysis of a critical infrastructure, i.e., the Saudi Arabian crude-oil distribution network. © 2013 IEEE.

Varona L.,University of Zaragoza | Sorensen D.,University of Aarhus
Genetics | Year: 2014

This work presents a model for the joint analysis of a binomial and a Gaussian trait using a recursive parametrization that leads to a computationally efficient implementation. The model is illustrated in an analysis of mortality and litter size in two breeds of Danish pigs, Landrace and Yorkshire. Available evidence suggests that mortality of piglets increased partly as a result of successful selection for total number of piglets born. In recent years there has been a need to decrease the incidence of mortality in pig-breeding programs. We report estimates of genetic variation at the level of the logit of the probability of mortality and quantify how it is affected by the size of the litter. Several models for mortality are considered and the best fits are obtained by postulating linear and cubic relationships between the logit of the probability of mortality and litter size, for Landrace and Yorkshire, respectively. An interpretation of how the presence of genetic variation affects the probability of mortality in the population is provided and we discuss and quantify the prospects of selecting for reduced mortality, without affecting litter size. © 2014 by the Genetics Society of America.

Mayoral A.,University of Zaragoza | Readman J.E.,University of Central Lancashire | Anderson P.A.,University of Birmingham
Journal of Physical Chemistry C | Year: 2013

In the current work, we present the analysis of Cd clusters encapsulated in zeolite A (LTA structure type) by means of aberration-corrected STEM. By a detailed analysis of the main crystallographic orientations, two different Cd species have been identified in the six-rings of the sodalite cage. This method of imaging is strongly sensitive to the atomic number Z, which has allowed us to observe at atomic level the distribution of the cadmium within the zeolite. Moreover, the stability of the compound formed has been tested with respect to the open atmosphere. © 2013 American Chemical Society.

Raventos J.,University of Alicante | Wiegand T.,Helmholtz Center for Environmental Research | De Luis M.,University of Zaragoza
Ecology | Year: 2010

A current focus of ecology is the investigation of spatial effects on population and community dynamics; however, spatiotemporal theory remains largely untested by empirical observations or experimental studies. For example, the segregation hypothesis predicts that intraspecific aggregation should increase the importance of intraspecific competition relative to interspecific competition, thereby enhancing local coexistence in plant communities. We applied recent methods of point pattern analysis to analyze a unique longterm data set on fully mapped seedling emergence and subsequent survival in a Mediterranean gorse shrubland after experimental fires and simulated torrential rainfall events. Our overall aim was to test if the observed spatial patterns were consistent with the segregation hypothesis during the entire community dynamics from early seedling emergence to the establishment of a mature community, i.e., we explored if the observed initial segregation did indeed prevent interspecific competition from becoming dominant. We used random labeling as the null model and specific test statistics to evaluate different biological effects of the spatial interactions that determine mortality. We found that mortality was clearly not random. Comparison of the probability of mortality in dependence on the distance to conspecific and to heterospecific plants showed that mortality was controlled almost entirely by intraspecific interactions, which is consistent with the segregation hypothesis. Dead plants were aggregated and segregated from surviving plants, indicating two-sided scramble competition. Spatial interactions were density dependent and changed their sign over the course of time from positive to negative when plants grew to maturity. The simulated torrential rainfall events and subsequent erosion caused nonspecific mortality of seedlings but did not reduce the prevalence of intraspecific competition. Our results provide support for the hypothesis that the spatial distribution of plants may profoundly affect competition and can be an important determinant in the coexistence of species and biodiversity. © 2010 by the Ecological society ot America.

Abstract: This article analyses empirically the main existing theories on income and population city growth: increasing returns to scale, locational fundamentals and random growth. To do this we consider a large database of urban, climatological and macroeconomic data from 1,173 US cities observed in 1990 and 2000. The econometric model is robust to the presence of spatial effects. Our analysis shows the existence of increasing returns and two distinct equilibria in per-capita income and population growth. We also find important differences in the structure of productive activity, unemployment rates and geographical location between cities in low-income and high-income regimes. © 2015 Regional Studies Association.

Salgado-Remacha F.J.,University of Zaragoza
Optics and Laser Technology | Year: 2016

Gerchberg-Saxton Algorithm is a common tool for designing Computer Generated Holograms. There exist some standard functions for evaluating the quality of the final results. However, the use of randomized initial guess leads to different results, increasing the variability of the evaluation functions values. This fact is especially detrimental when the computing time is elevated. In this work, a new tool is presented, able to describe the fidelity of the results with a notably reduced variability after multiple attempts of the Gerchberg-Saxton Algorithm. This new tool results very helpful for topical fields such as 3D digital holography. © 2016 Elsevier Ltd

Santolaria J.,University of Zaragoza | Gines M.,General Motors
Robotics and Computer-Integrated Manufacturing | Year: 2013

Currently, the results of a robot calibration procedure are expressed generally in terms of the position and orientation error for a set of locations and orientations, which have been obtained from the previously identified kinematic parameters. In this work, a technique is presented to evaluate the calibration uncertainty for a robot arm calibrated using the circle point analysis method. The method developed is based on the probability distribution propagation calculation recommended by the Guide to the Expression of Uncertainty of Measurement and on the Monte Carlo method. This method makes it possible to calculate the uncertainty in the identification of each single robot parameter, and thus, to estimate the robot positioning uncertainty due to the calibration uncertainty, rather than based on a single set locations and orientations that are previously defined for a unique set of identified parameters. Additionally, this technique allows for the establishment of the best possible conditions for the data capture test, which identifies parameters and determines which of them have the least possible calibration uncertainty. This determination is based on the variables involved in the data capture process by propagating their influence up to the final robot accuracy. © 2012 Elsevier Ltd. All rights reserved.

Enriquez J.A.,University of Zaragoza
Annual Review of Physiology | Year: 2016

Since the discovery of the existence of superassemblies between mitochondrial respiratory complexes, such superassemblies have been the object of a passionate debate. It is accepted that respiratory supercomplexes are structures that occur in vivo, although which superstructures are naturally occurring and what could be their functional role remain open questions. The main difficulty is to make compatible the existence of superassemblies with the corpus of data that drove the field to abandon the early understanding of the physical arrangement of the mitochondrial respiratory chain as a compact physical entity (the solid model). This review provides a nonexhaustive overview of the evolution of our understanding of the structural organization of the electron transport chain from the original idea of a compact organization to a view of freely moving complexes connected by electron carriers. Today supercomplexes are viewed not as a revival of the old solid model but rather as a refined revision of the fluid model, which incorporates a new layer of structural and functional complexity. Copyright © 2016 by Annual Reviews. All rights reserved.

Perez-Lopez F.R.,University of Zaragoza | Chedraui P.,High Risk Pregnancy Labor and Delivery Unit
Archives of Gynecology and Obstetrics | Year: 2010

Background: Chagas disease, caused by the Trypanosoma cruzi infection, is an endemic cause of morbidity and mortality in Latin America. Infection during pregnancy may increase the risk for adverse maternal-foetal outcome. Methods: Review of significant articles regarding maternal-foetal T. cruzi infection in free-vector non-endemic regions. Results: Vertical transmission, even in vector-free world regions, occurs in 1 out of 20 seropositive mothers. T. cruzi infection increases the risk of miscarriage, preterm birth and neonatal infection which may cause infant death or severe sequelae. Prevention of T. cruzi vertical transmission is not feasible, although early diagnosis allows appropriate treatment of newborns with a 100% efficacy. The present document will recall the importance of T. cruzi mother-to-child transmission and maternal-foetal consequences in non-endemic areas. Conclusion: It is highly recommended that infected pregnant women in non-endemic regions be accurately assessed. © 2010 Springer-Verlag.

Alonso J.J.,University of Malaga | Fernandez J.F.,University of Zaragoza
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

By tempered Monte Carlo simulations, we study site-diluted Ising systems of magnetic dipoles. All dipoles are randomly placed on a fraction x of all L3 sites of a simple cubic lattice, and point along a given crystalline axis. For xc

Estrada-Pena A.,University of Zaragoza | Ayllon N.,Institute Investigacion en Recursos Cinegeticos | de la Fuente J.,Institute Investigacion en Recursos Cinegeticos | de la Fuente J.,Oklahoma State University
Frontiers in Physiology | Year: 2012

Recent advances in climate research together with a better understanding of tick-pathogen interactions, the distribution of ticks and the diagnosis of tick-borne pathogens raise questions about the impact of environmental factors on tick abundance and spread and the prevalence and transmission of tick-borne pathogens. While undoubtedly climate plays a role in the changes in distribution and seasonal abundance of ticks, it is always difficult to disentangle factors impacting on the abundance of tick hosts from those exerted by human habits. All together, climate, host abundance, and social factors may explain the upsurge of epidemics transmitted by ticks to humans. Herein we focused on tick-borne pathogens that affect humans with epidemic potential. Borrelia burgdorferi s.l. (Lyme disease), Anaplasma phagocytophilum (human granulocytic anaplasmosis), and tick-borne encephalitis virus (tick-borne encephalitis) are transmitted by Ixodes spp. Crimean-Congo hemorrhagic fever virus (Crimean-Congo hemorrhagic fever) is transmitted by Hyalomma spp. In this review, we discussed how vector tick species occupy the habitat as a function of different climatic factors, and how these factors impact on tick survival and seasonality. How molecular events at the tick-pathogen interface impact on pathogen transmission is also discussed. Results from statistically and biologically derived models are compared to show that while statistical models are able to outline basic information about tick distributions, biologically derived models are necessary to evaluate pathogen transmission rates and understand the effect of climatic variables and host abundance patterns on pathogen transmission. The results of these studies could be used to build early alert systems able to identify the main factors driving the subtle changes in tick distribution and seasonality and the prevalence of tick-borne pathogens. © 2012 Estrada-Peña, Ayllón and de la Fuente.

Utama M.I.B.,Nanyang Technological University | Belarre F.J.,CSIC - Institute of Materials Science | Magen C.,University of Zaragoza | Peng B.,Nanyang Technological University | And 3 more authors.
Nano Letters | Year: 2012

The requirement of lattice matching between a material and its substrate for the growth of defect-free heteroepitaxial crystals can be circumvented with van der Waals epitaxy (vdWE). However, the utilization and characteristics of vdWE in nonlamellar/nonplanar nanoarchitectures are still not very well-documented. Here we establish the characteristics of vdWE in nanoarchitectures using a case study of ZnO nanowire (NW) array on muscovite mica substrate without any buffer/seed layer. With extensive characterizations involving electron microscopy, diffractometry, and the related analyses, we conclude that the NWs grown via vdWE exhibit an incommensurate epitaxy. The incommensurate vdWE allows a nearly complete lattice relaxation at the NW-substrate heterointerface without any defects, thus explaining the unnecessity of lattice matching for well-crystallized epitaxial NWs on muscovite mica. We then determine the polarity of the NW via a direct visualization of Zn-O dumbbells using the annular bright field scanning transmission electron miscroscopy (ABF-STEM) in order to identify which atoms are at the base of the NWs and responsible for the van der Waals interactions. The information from the ABF-STEM is then used to construct the proper atomic arrangement at the heterointerface with a 3D atomic modeling to corroborate the characteristics of the incommensurate vdWE. Our findings suggest that the vdWE might be extended for a wider varieties of compounds and epitaxial nanoarchitectures to serve as a universal epitaxy strategy. © 2012 American Chemical Society.

Redondo J.,University of Zaragoza | Redondo J.,Max Planck Institute for Physics
Journal of Cosmology and Astroparticle Physics | Year: 2015

Hidden photons, gauge bosons of a U(1) symmetry of a hidden sector, can constitute the dark matter of the universe and a smoking gun for large volume compactifications of string theory. In the sub-eV mass range, a possible discovery experiment consists on searching the copious flux of these particles emitted from the Sun in a helioscope setup à la Sikivie. In this paper, we compute in great detail the flux of HPs from the Sun, a necessary ingredient for interpreting such experiments. We provide a detailed exposition of transverse photon-HP oscillations in inhomogenous media, with special focus on resonance oscillations, which play a leading role in many cases. The region of the Sun emitting HPs resonantly is a thin spherical shell for which we justify an averaged-emission formula and which implies a distinctive morphology of the angular distribution of HPs on Earth in many cases. Low mass HPs with energies in the visible and IR have resonances very close to the photosphere where the solar plasma is not fully ionised and requires building a detailed model of solar refraction and absorption. We present results for a broad range of HP masses (from 0-1 keV) and energies (from the IR to the X-ray range), the most complete atlas of solar HP emission to date. © 2015 IOP Publishing Ltd and Sissa Medialab srl.

Mayoral A.,University of Zaragoza | Llamosa D.,CSIC - Institute of Materials Science | Huttel Y.,CSIC - Institute of Materials Science
Chemical Communications | Year: 2015

Core@shell Co@Au nanoparticles of around 8 nm have been produced by the inert gas condensation method, revealing for the first time that most of the nanoparticles exhibit an icosahedral shape in agreement with the theoretical prediction. Additionally, we report the existence of a novel morphology which consists of a Co icosahedron surrounded by fcc Au facets, reported here for the first time. © 2015 The Royal Society of Chemistry.

The identification of information professional profiles is necessary in order to develop studies for the current labor market and to improve professional development for students. A literature review was carried out on selected papers published within the last two decades. Findings indicate that faculty must address the definition and acquisition of skills to prepare students for a dynamic and constantly changing professional environment.

Mba M.,University of Padua | Jimenez A.I.,University of Zaragoza | Moretto A.,Univers