A non-cylindrical model of development of the Hercynian belt allochthonous terranes

[Resumen] Se propone un modelo no cilíndrico para el desarrollo del Cinturón Hercínico Europeo. Los terrenos alóctonos fuertemente trasladados que forman parte de él se componen de una mezcla de unidades catazonales y ofiolíticas, así como de fragmentos del margen continental de Gondwana. La disposición de estos terrenos y sus relaciones con la paleogeografía de Gondwana, así como las estructuras que muestran, sugieren que se emplazaron de manera oblícua, en una dirección que formaba un pequeño ángulo con el margen de este continente. El alóctono podría estar ligado al desarrollo de un arco de islas o de una subplaca con forma de cuña en la parte meridional de la placa Báltica. Con posterioridad a su emplazamiento, la convergencia entre Gondwana y Laurasia, que habría incluido movimientos transcurrentes esencialmente dextros, sería responsable de la complejidad actual del orógeno.[Abstract] A case is made for a non-cylindrical development of the European Hercynian belt. Far-travelled allochthonous terranes in it consits of a mixture of units including catazonal ones, ophiolites and units derived from the continental margin of Gondwana. Considerations upon the disposition of the terranes, their relationships with the paleogeography of the Gondwana realm and the structures in them, suggest that their emplacement took place in an oblique fashion at a small angle to the margin of this continent. The proposed allochthon could be related to the development of an island arc or a wedge-like subplate in the southern part of the Baltica plate. Later, convergence between Gondwana and Laurussia, involving transcurrent, mostly dextral movements, would account for the present complexity of the belt

Understanding how customers engage with social tourism websites

Purpose: This paper aims to analyse the effect of technology acceptance variables on customer attitude and customer engagement behaviours (CEB) with social tourism websites (STWs). Design/methodology/approach: An empirical study was carried out with 346 customers. A model was developed to analyse the relationships between CEB and their determinants. Partial least squares – structural equation modelling was used to test the model. Findings: Customers’ perceptions of enjoyment, ease of use, usefulness and trustworthiness positively influence their attitude towards STWs and their subsequent engagement behaviours [purchases, word of mouth (WOM) and referrals]. Originality/value: This study develops and empirically tests a model that analyses the impact of technology acceptance model variables on CEB, both transactional (customer purchases) and non-transactional (customer WOM, referrals and feedback), in the context of STWs

Influence of hydrogen peroxide in the tribocorrosion behaviour of a CoCrMo biomedical alloy

This paper studies the influence of hydrogen peroxide (H2O2) in simulated body fluids on the wear and corrosion behaviour of a CoCrMo biomedical alloy. CoCrMo are passive materials commonly used in prosthesis and implants because of its high corrosion resistance and mechanical properties. Hydrogen peroxide is produced by bacteria and leukocytes as a consequence of an inflammatory reaction which may modify the tribo-electrochemical response of metals implanted in the human body. Indeed, the oxidizing environment generated by the presence of the peroxide increases the metal dissolution rate. Electrochemical and tribocorrosion tests were carried out in a PBS solution with different addition of H2O2 (0.5, 2, 4 and 12%).The authors acknowledge Generalitat Valencia for the Gerónimo Forteza financial support and to the Electron Microscopy Service of the UPV for the SEM images

Tectonothermal evolution associated with crustal escale extension: an hercynian example from the Tormes gneiss dome (NW Salamanca, Iberian Massif)

[Abstract] The tectonothermal Variscan evolution ofthe Tormes Gneiss Dome is controlled by a subhorizontal ductile shear zone of crustal scale and extensional characteristics, that induced a quick exhumation ofthe deep parts ofthe metamorphic complex during crustal thinning. The shearing affected a broad band of metamorphic rocks but, as the temperature decreased, became progressively concentrated in a low-grade ductile detachment that separates two distinct units, characterized by their lithology and different tectonothermal evolution. Kinematic indicators in non-coaxial fabrics show a displacement of the hangingwall to the SE, i. e., parallel to the trend of the foldbelt. The subhorizontal shearing is related to the extensional collapse ofthe variscan crust, previously thickened during the collision tectonics

A spiral structure in the disk of EX Draconis on the rise to outburst maximum

We report on the R-band eclipse mapping analysis of high-speed photometry of the dwarf nova EX Dra on the rise to the maximum of the November 1995 outburst. The eclipse map shows a one-armed spiral structure of ~180 degrees in azimuth, extending in radius from R ~0.2 to 0.43 R_{L1} (where R_{L1} is the distance from the disk center to the inner Lagrangian point), that contributes about 22 per cent of the total flux of the eclipse map. The spiral structure is stationary in a reference frame co-rotating with the binary and is stable for a timescale of at least 5 binary orbits. The comparison of the eclipse maps on the rise and in quiescence suggests that the outbursts of EX Dra may be driven by episodes of enhanced mass-transfer from the secondary star. Possible explanations for the nature of the spiral structure are discussed.Comment: To appear in the Astrophysical Journal Letters; 8 pages, 2 figures; coded with AAS latex styl

An analytical methodology to derive power models based on hardware and software metrics

The use of models to predict the power consumption of a system is an appealing alternative to wattmeters since they avoid hardware costs and are easy to deploy. In this paper, we present an analytical methodology to build models with a reduced number of features in order to estimate power consumption at node level. We aim at building simple power models by performing a per-component analysis (CPU, memory, network, I/O) through the execution of four standard benchmarks. While they are executed, information from all the available hardware counters and resource utilization metrics provided by the system is collected. Based on correlations among the recorded metrics and their correlation with the instantaneous power, our methodology allows (i) to identify the significant metrics; and (ii) to assign weights to the selected metrics in order to derive reduced models. The reduction also aims at extracting models that are based on a set of hardware counters and utilization metrics that can be obtained simultaneously and, thus, can be gathered and computed on-line. The utility of our procedure is validated using real-life applications on an Intel Sandy Bridge architecture

Reconstructing the origins and the biogeography of species’ genomes in the highly reticulate allopolyploid-rich model grass genus Brachypodium using minimum evolution, coalescence and maximum likelihood approaches

The identification of homeologous genomes and the biogeographical analyses of highly reticulate allopolyploid-rich groups face the challenge of incorrectly inferring the genomic origins and the biogeographical patterns of the polyploids from unreliable strictly bifurcating trees. Here we reconstruct a plausible evolutionary scenario of the diverging and merging genomes inherited by the diploid and allopolyploid species and cytotypes of the model grass genus Brachypodium. We have identified the ancestral Brachypodium genomes and inferred the paleogeographical ranges for potential hybridization events that originated its allopolyploid taxa. We also constructed a comprehensive phylogeny of Brachypodium from five nuclear and plastid genes using Species Tree Minimum Evolution allele grafting and Species Network analysis. The divergence ages of the lineages were estimated from a consensus maximum clade credibility tree using fossil calibrations, whereas ages of origin of the diploid and allopolyploid species were inferred from coalescence Bayesian methods. The biogeographical events of the genomes were reconstructed using a stratified Dispersal-Extinction-Colonization model with three temporal windows. Our combined Minimum Evolution-coalescence-Bayesian approach allowed us to infer the origins and the identities of the homeologous genomes of the Brachypodium allopolyploids, matching the expected ploidy levels of the hybrids. To date, the current extant progenitor genomes (species) are only known for B. hybridum. Putative ancestral homeologous genome have been inherited by B. mexicanum, ancestral and recent genomes by B. boissieri, and only recently evolved genomes by B. retusum and the core perennial clade allopolyploids (B. phoenicoides, B. pinnatum 4x, B. rupestre 4x). We dissected the complex spatio-temporal evolution of ancestral and recent genomes and have detected successive splitting, dispersal and merging events for dysploid homeologous genomes in diverse geographical scenarios that have led to the current extant taxa. Our data support Mid-Miocene splits of the Holarctic ancestral genomes that preceded the Late Miocene origins of Brachypodium ancestors of the modern diploid species. Successive divergences of the annual B. stacei and B. distachyon diploid genomes were implied to have occurred in the Mediterranean region during the Late Miocene-Pliocene. By contrast, a profusion of splits, range expansions and different genome mergings were inferred for the perennial diploid genomes in the Mediterranean and Eurasian regions, with sporadic colonizations and further mergings in other continents during the Quaternary. A reliable biogeographical scenario was obtained for the Brachypodium genomes and allopolyploids where homeologous genomes split from their respective diploid counterpart lineages in the same ancestral areas, showing similar or distinct dispersals. By contrast, the allopolyploid taxa remained in the same ancestral ranges after hybridization and genome doubling events. Our approach should have utility in deciphering the genomic composition and the historical biogeography of other allopolyploid-rich organismal groups, which are predominant in eukaryotes