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Implications of burial alterations on luminescence dating of archaeological ceramics

  • Zacharias, Nikolaos
  • Buxeda i Garrigós, Jaume
  • Mommsen, Hans
  • Schwedt, Alexander
  • Kilikoglou, Vasilis
Recent mineralogical studies on archaeological pottery samples report significant variations in alkali metal concentrations due to environmental alterations during burial. Here we examine the effects of potassium (K) leaching on luminescence dating. The effect on the estimation of the dose rate is studied by considering four models of leaching (exponential, linear, early and late) and their impact on fine- and coarse-grain dating are calculated. The modeling approaches are applied to two cases of pottery in which evidence for alteration was found. Additionally, TL dating performed on pottery of one of the studied cases, indicates the importance of leaching effects on absolute dating measurements.
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A contribution to the study of post-depositional alterations of pottery using TL dating analysis

  • Zacharias, Nikolaos
  • Schwedt, Alexander
  • Buxeda i Garrigós, Jaume
  • Michael, Christodoulos T.
  • Mommsen, Hans
  • Kilikoglou, Vasilis
In luminescence dating, the potassium concentration significantly contributes to the dose rate value in the age estimation. Within this study, fine-grain thermoluminescence dating has been applied on sherds of calcareous pottery of known age, excavated at a Roman site in Mallorca, Spain. For those of the samples that showed signs of severe potassium leaching, according to chemical and mineralogical examination, the thermoluminescence analysis provided overestimated dates. By using the known archaeological age of the samples, a corrected dose rate value can be estimated which provides the potassium concentration averaged for the burial period. Finally, a step-like model can then be used to estimate the fraction of the burial period after which most of the alteration effects took place.
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Multistationary and oscillatory modes of free radicals generation by the mitochondrial respiratory chain revealed by a bifurcation analysis.

  • Selivanov, Vitaly A.
  • Cascante i Serratosa, Marta
  • Friedman, Mark
  • Schumaker, Mark F.
  • Trucco, Massimo
  • Votyakova, Tatyana V.
The mitochondrial electron transport chain transforms energy satisfying cellular demand and generates reactive oxygen species (ROS) that act as metabolic signals or destructive factors. Therefore, knowledge of the possible modes and bifurcations of electron transport that affect ROS signaling provides insight into the interrelationship of mitochondrial respiration with cellular metabolism. Here, a bifurcation analysis of a sequence of the electron transport chain models of increasing complexity was used to analyze the contribution of individual components to the modes of respiratory chain behavior. Our algorithm constructed models as large systems of ordinary differential equations describing the time evolution of the distribution of redox states of the respiratory complexes. The most complete model of the respiratory chain and linked metabolic reactions predicted that condensed mitochondria produce more ROS at low succinate concentration and less ROS at high succinate levels than swelled mitochondria. This prediction was validated by measuring ROS production under various swelling conditions. A numerical bifurcation analysis revealed qualitatively different types of multistationary behavior and sustained oscillations in the parameter space near a region that was previously found to describe the behavior of isolated mitochondria. The oscillations in transmembrane potential and ROS generation, observed in living cells were reproduced in the model that includes interaction of respiratory complexes with the reactions of TCA cycle. Whereas multistationarity is an internal characteristic of the respiratory chain, the functional link of respiration with central metabolism creates oscillations, which can be understood as a means of auto-regulation of cell metabolism.
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When decisions of others matter to me: an electrophysiological analysis.

  • Marco Pallarés, Josep
  • Krämer, Ulrike M.
  • Strehl, Saskia
  • Schröder, Andrea
  • Münte, Thomas F.
Background: Actions of others may have immediate consequences for oneself. We probed the neural responses associated with the observation of another person"s action using event-related potentials in a modified gambling task. In this task a"performer" bet either a higher or lower number and could win or lose this amount. Three different groups of"observers" were also studied. The first (neutral) group simply observed the performer"s action, which had no consequences for the observers. In the second (parallel) group, wins/losses of the performer were paralleled by similar wins and losses by the observer. In the third (reverse) group, wins of the performer led to a loss of the observer and vice versa. Results: ERPs of the performers showed a mediofrontal feedback related negativity (FRN) to losses. The neutral and parallel observer groups did similarly show an FRN response to the performer"s losses with a topography indistinguishable from that seen in the performers. In the reverse group, however, the FRN occurred for wins of the performer which translated to losses for the observer. Conclusions: Taking into account previous experiments, we suggest that the FRN response in observers is driven by two evaluative processes (a) related to the benefit/loss for oneself and (b) related to the benefit/loss of another person
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Steven Spielberg descubre Tintín con El secreto del unicornio

  • Romea Castro, Celia
El secreto del Unicornio es la décima novela gráfica de la serie Las aventuras de Tintín,3 del autor belga Georges Prosper Remi, más conocido por su seudónimo Hergé. El relato que ahora presentamos5 es la primera parte del que le sigue, El tesoro de Rackham el Rojo, y cinematográficamente corresponderá a una futura segunda parte del filme. Tintín, joven reportero belga, se mete a menudo en problemas por defender causas justas.
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Claves pedagógicas que guían la práctica educativa de una maestra

  • Orozco Martínez, Susana
  • Gabbarini, Patricia A.
Podeu consultar el simposi complet a: http://hdl.handle.net/2445/50680, La investigación El saber profesional en docentes de educación primaria y sus implicaciones en la formación inicial del profesorado: estudios de caso (Investigación financiada por el Ministerio de Economía y Competitividad, actualmente en desarrollo, con diez docentes participantes) pretende ubicar el saber profesional de docentes en una relación pensante con lo que sucede en sus aulas, con su alumnado y con ellos mismos. El presente artículo centra el análisis en la investigación realizada con una docente de educación infantil, Esther, maestra de Educación infantil, de una escuela pública de la localidad catalana de La Garriga. Tiene a su cargo 13 niñas y 11 niños de 3 años. Se indaga los modos y maneras en como despliega el saber profesional desde una perspectiva analítica de su experiencia, con la intención de descubrir las claves pedagógicas que guían su práctica, con el objetivo de transferir los conocimientos a la formación universitaria.
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From Full stopping to transparency in a holographic model of heavy ion collisions

  • Casalderrey Solana, Jorge
  • Heller, Michal P.
  • Mateos, David (Mateos Solé)
  • Van der Schee, Wilke
We numerically simulate planar shock wave collisions in anti-de Sitter space as a model for heavy ion collisions of large nuclei. We uncover a crossover between two different dynamical regimes as a function of the collision energy. At low energies the shocks first stop and then explode in a manner approximately described by hydrodynamics, in close similarity with the Landau model. At high energies the receding fragments move outwards at the speed of light, with a region of negative energy density and negative longitudinal pressure trailing behind them. The rapidity distribution of the energy density at late times around midrapidity is not approximately boost invariant but Gaussian, albeit with a width that increases with the collision energy.
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Cherenkov mesons as in-medium quark energy loss

  • Casalderrey Solana, Jorge
  • Fernández, Daniel (Fernández Moreno)
  • Mateos, David (Mateos Solé)
We recently showed that a heavy quark moving sufficiently fast through a quark-gluon plasma may lose energy by Cherenkov-radiating mesons [1]. Here we review our previous holographic calculation of the energy loss in N=4 Super Yang-Mills and extend it to longitudinal vector mesons and scalar mesons. We also discuss phenomenological implications for heavy-ion collision experiments. Although the Cherenkov energy loss is an O(1/Nc) effect, a ballpark estimate yields a value of dE/dx for Nc=3 which is comparable to that of other mechanisms.
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Holographic isotropization linearized

  • Heller, Michal P.
  • Mateos, David (Mateos Solé)
  • Van der Schee, Wilke
  • Triana Iglesias, Miquel
The holographic isotropization of a highly anisotropic, homogeneous, strongly coupled, non-Abelian plasma was simplified in ref. [1] by linearizing Einstein"s equations around the final, equilibrium state. This approximation reproduces the expectation value of the boundary stress tensor with a 20% accuracy. Here we elaborate on these results and extend them to observables that are directly sensitive to the bulk interior, focusing for simplicity on the entropy production on the event horizon. We also consider next-to-leading-order corrections and show that the leading terms alone provide a better description of the isotropization process for the states that are furthest from equilibrium.
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Contribución al conocimiento de la geología del depósito de Au-Cu de La Pava (Península de Azuero, Panamá)

  • Corral, Isaac
  • Cardellach López, Esteve
  • Gómez-Gras, David
  • Canals i Sabaté, Àngels
The «La Pava» Au-Cu deposit is hosted by a vulcanosedimentary sequence, named Ocú Formation,developed in an island arc environment that resulted from the subduction of the Nazca Plate beneath the Caribbean Plate during the Cretaceous times. The deposit consists of disseminations and stockworks of pyrite and chalcopyrite accompanied by barite, quartz and carbonates. Three hydrothermal alteration zones have been recognized: silicic, argillic and propilityc, typical of gold-related high sulfidation systems. A supergenic alteration overprints the hydrothermal alterations developing a cap rich in silica and Feoxides. The detailed study of the Ocú Fm. indicates that the sulfides and the accompanying gold was formed in a submarine environment. Therefore we suggest that «La Pava» represents an Au-Cu hybrid deposit between high sulphidation epithermal and VMS types, which are found in volcanogenic massive sulphide environments.
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