Iglesias evangélicas, vida cotidiana y AMLO . Un acercamiento etnográfico.

A lo largo de su última campaña por la presidencia de la República, y durante los primeros meses de su gobierno, el presidente Andrés Manuel López Obrador ha impregnado su discurso político de ética y moral cristianas y, con ello, ha reavivado el debate sobre el Estado laico en México. A través del ejercicio etnográfico, el presente artículo describe la evangelización cotidiana, hecha desde el ámbito privado, de los bautistas en la ciudad de Puebla, Pue. Asimismo, evidencia cómo la creencia personal de AMLO ha trascendido al ámbito público, transformando el panorama político de las religiones evangélicas. Por último, invita a reflexionar sobre la diversidad del mundo evangélico

The Eye and the Zika Virus

Ocular involvement in Zika virus (ZIKV) infection can be present both in adults and infants as acquired and congenital diseases respectively. Through experimental studies, there has been clarified important mechanisms of ocular pathogenesis that allow the establishment of potential objectives for antiviral drugs development. The spread of the virus at the ocular level could be hematogenous or axonal, however the hematogenous route through the choroid is suggested as the most important initial mechanism for infection. Ocular manifestations vary according to the age of presentation, being mild and self-limited in adults and potentially devastating in children, related to congenital Zika syndrome (CZS). Ocular diagnosis is made based in clinical features and contact/travel history to countries of epidemiological importance; fundoscopy, optical coherence tomography, fluoresceinic/green indocianine angiography, cultures, serological and molecular tests are useful diagnostic tools. Ocular management is focused according to the clinical context of each patient. Prevention is carried out in a comprehensive manner and further research is directed to vaccine development and specific antiviral treatment. Proper attention requires a multidisciplinary team in order to reach complete visual evaluation and early rehabilitation

Control of lateral composition distribution in graded films of soluble solid systems A1-xBx by partitioned dual-beam pulsed laser deposition

Altres ajuts: AGAUR agency (project 2017SGR)Lateral compositionally-graded thin films are powerful media for the observation of phase boundaries aswell as for high-throughputmaterials exploration.We herein propose amethod to prepare epitaxial lateral compositionally-graded films using a dual-beampulsed laser deposition (PLD)method with two targets separated by a partition. Tuning the ambient pressure and the partition-substrate gap makes it possible to control of the gradient length of the deposits at the small sizes (≤ 10 mm) suitable for commercial oxide single crystal substrates. A simple Monte Carlo simulation qualitatively reproduced the characteristic features of the lateral thickness distribution. To demonstrate this method, we prepared (1-x)PbTiO-xPbZrO and (1-x)LaMnOLaSrMnO films with lateral composition gradient widths of 10 and 1 mm, respectively, with the partitioned dual PLD

Mycobacterium tuberculosis and Cytomegalovirus Colitis in a Renal Transplant Patient: A Case Report

Q3Q2Pacientes con trasplante de riñónPacientes con Infección por citomegalovirusPacientes con Diarrea crónicaChronic diarrhea is a common reason for consultation in renal transplant patients. Cytomegalovirus infection is the cause of chronic diarrhea of infectious origin in 50% of cases, but coinfection with tuberculosis is rare. We present the case of a renal transplant patient with chronic diarrhea, with a finding of left colon colitis and positive microbiological studies in biopsy for tuberculosis and cytomegalovirus. The patient received valganciclovir and anti-tubercular treatment with adequate evolution. Immunosuppressed patients may have diarrhea secondary to opportunistic infections; therefore, an algorithm for early diagnosis and treatment is recommended.https://orcid.org/0000-0002-8892-9652https://orcid.org/0000-0001-9852-749Xhttps://orcid.org/0000-0002-4069-3230https://orcid.org/0000-0002-6772-2943https://orcid.org/0000-0002-4100-3529Revista Internacional - IndexadaBS

Magnetostructural coupling, magnetic ordering, and cobalt spin reorientation in metallic P r0.5 S r0.5Co O3 cobaltite

In half-doped Pr0.50A0.50CoO3 metallic perovskites, the spin-lattice coupling brings about distinct magnetostructural transitions for A=Ca and A=Sr at temperatures close to ~100 K. However, the ground magnetic properties of Pr0.50Sr0.50CoO3 (PSCO) strongly differ from Pr0.50Ca0.50CoO3 ones, where a partial Pr3+ to Pr4+ valence shift and Co spin transition makes the system insulating below the transition. This paper investigates and describes the relationship between the Imma¿I4/mcm symmetry change [Padilla-Pantoja, García-Muñoz, Bozzo, Jirák, and Herrero-Martín, Inorg. Chem. 53, 12297 (2014)] and the original magnetic behavior of PSCO versus temperature and external magnetic fields. The FM1 and FM2 ferromagnetic phases, above and below the magnetostructural transition (TS1~120K) have been investigated. The FM2 phase of PSCO is composed of [100] FM domains, with magnetic symmetry Im'm'a (mx¿0, mz=0). The magnetic space group of the FM1 phase is Fm'm'm (with mx=my). Neutron data analyses in combination with magnetometry and earlier reports results agrees with a reorientation of the magnetization axis by 45° within the ab plane across the transition, in which the system retains its metallic character. The presence below TS1 of conjugated magnetic domains, both of Fm'm'm symmetry but having perpendicular spin orientations along the diagonals in the xy plane of the tetragonal unit cell, is at the origin of the anomalies observed in the macroscopic magnetization. A relatively small field µ0H[¿z]¿30mT is able to reorient the magnetization within the ab plane, whereas a higher field (µ0H[¿z]¿1.2T at 2 K) is necessary to align the Co moments perpendicular to the ab plane. Such a spin reorientation, in which the orbital and spin components of the Co moment rotate joined by 45°, was not observed previously in analogous cobaltites without praseodymium

Double-cell superstructure and vacancy ordering in tensile-strained metallic thin films of P r0.50 C a0.50Co O3 on LaAl O3

The Pr-based cobaltate Pr0.5Ca0.5CoO3 (PCCO) presents in bulk form a singular simultaneous valence and spin-state transition that turns the metallic state into insulator, and displays a large and ultrafast photoresponse in the insulating phase. Epitaxial thin films of PCCO have been grown by deposition on LaAlO3(001) (LAO) substrate, chosen to minimize the mismatch with the film. The films grow epitaxially with two times the substrate periodicity (2a0×2a0×2a0) and the long perovskite axis perpendicular to the surface. We report a reduction of the structural symmetry from Pnma (bulk) to P212121 (film). The P212121 symmetry revealed by synchrotron x ray remains at low temperatures. These PCCO films are metallic, and ferromagnetic below TC=170K, confirming the stabilization of excited Co3+ spin states and the suppression of the concurrent Co spin-state, valence, and metal-insulator transitions. Z-contrast imaging and electron-energy-loss spectroscopy elemental maps reveal long-range ordered oxygen vacancy planes unexpectedly stacking parallel to the interface, in spite of the tensile character of the PCCO/LAO heterostructure. In contrast to the general tendency reported for strained La0.5Sr0.5CoO3-d (LSCO) films, we show that a nominal tensile strain can be also compatible with the presence of alternating O vacancy planes parallel to the interface, instead of perpendicular to it. That occurs thanks to the double cell of the film and the formation of the (1/2, 1/2, 1/2) superstructure studied in this work. These results expand the possibilities of controlling interfacial physical properties via engineering of ordered oxygen-defect structures in strongly correlated oxides

On the Electrochemical Activation of Nanoporous Reduced Graphene Oxide Electrodes Studied by In Situ/Operando Electrochemical Techniques

Due to the difficult access of the electrolyte into the nanoconfined space of nanoporous reduced graphene oxide (rGO) electrodes, achieving the optimal electrochemical performance of these devices becomes a challenge. In this work, the dynamics of interfacial-governed phenomena are investigated during a voltage-controlled electrochemical activation of nanoporous rGO electrodes that leads to an enhanced electrochemical performance in terms of areal capacitance and electrochemical impedance. In situ/operando characterization techniques are used to reveal the dynamics of the irreversible material changes introduced during the activation process, including ionic diffusion and water confinement within the nanopores, along with the reduction of oxygenated groups and the decrease of the rGO interlayer distance. Furthermore, operando techniques are used to uncover the origin of the complex polarization-dependent dynamic response of rGO electrodes. The study reveals that the reversible protonation/deprotonation of remaining functional groups and the cation electro-adsorption/desorption process in the graphene basal plane govern the pseudocapacitive performance of nanoporous rGO electrodes. This work brings new understanding of the complex interplay between surface chemistry, ion confinement, and desolvation processes occurring during electrochemical cycling in nanoporous rGO electrodes, offering new insights for designing high-performing electrodes based on nanoporous rGO

Spin-lattice coupling in strongly correlated cobalt oxides investigated by synchrotron and neutron techniques

El trabajo que se presenta en esta tesis has sido realizado entre Enero del 2011 y Diciembre del 2015 en el Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), con la colaboración del Sincrotrón ALBA (Cerdanyola del Vallès). Los óxidos de cobalto presentan numerosas propiedades funcionales y fenómenos físicos de interés como magnetorresistencia gigante, doble intercambio, separación de fases, cambios de estado de espín, transiciones metal-aislante (TMI), alto poder termoeléctrico, difusión de oxígeno, conducción mixta, orden de carga, orbital, de estado de espín o superconductividad, entre otras propiedades. Presentan interés desde un punto de vista fundamental y debido a su potencial aplicación en campos como la espintrónica, los dispositivos termoeléctricos, como materiales para SOFC, catálisis, sensores, etc.. Destaca en algunas cobaltitas la singular habilidad de los iones del cobalto para adoptar diferentes estados de espín. Ello proporciona un grado de libertad adicional, que además favorece el acoplamiento espín-red, y tiene efectos importantes sobre la movilidad electrónica, la respuesta termoeléctrica y catalítica, o la estabilidad estructural y magnética. Esta tesis investiga la influencia de las inestabilidades del estado de espín en cobaltitas con acoplamiento espín-red. Aborda cuatro clases principales de cobaltitas correlacionadas, con diferentes estructuras, preparadas o fabricadas principalmente (pero no sólo) en forma másica: LnCoO3, Ln0.50Sr0.50CoO3, LnBaCoO5.50 and Ba2Co9O14. Distintas transiciones estructurales, electrónicas, magnéticas, magnetostructurales y metal-aislante han sido investigadas mediante experimentos en fuentes de radiación sincrotrón y de neutrones. Entre ellas, los sincrotrones ALBA (Barcelona), ESRF (Grenoble), SLS ((PSI, Switzerland)) y Helmholtz-Zentrum Berlin-BESSY II (HZB, Berlín), el reactor de neutrones ILL (Grenoble) y la fuente de espalación SINQ (PSI, Switzerland). A partir de experimentos de difracción de polvo mediante neutrones (NPD) y radiación sincrotrón (SXRPD), espectroscopías de absorción y emisión de rayos-X (XAS y XES) y dicroísmo magnético circular (XMCD). El interés por los sistemas con fórmula general LnCoO3 reside en la naturaleza de las transiciones de estado de espín (SS) y los dos posibles escenarios propuestos para el compuesto de referencia LaCoO3: LS→LS+HS→HS o LS→IS→HS. Nosotros hemos combinado el análisis de datos de absorción XAS con difracción de neutrones para comprender la influencia de la configuración de espín sobre la evolución de las estructuras cristalinas, y su variación en el diagrama de fases aumentando la distorsión de las cobaltitas LnCoO3. En el caso de la inesperada segunda transición magnética que muestra la cobaltita metálica Pr0.50Sr0.50CoO3 , la resolución de las estructuras cristalinas y magnéticas que aquí se presenta, junto a la characterización del momento orbital, han sido cruciales para entender el mecanismo de la transición magnetoestructural que presenta este compuesto. La síntesis de otros compuestos similares nos ha permitido trazar las propiedades magnéticas y electrónicas de las cobaltitas semi-dopadas ricas en estroncio de la familia Ln0.50(Sr, A)0.50CoO3 (A=Ba, Ca). Se han examinado cuidadosamente las complejas propiedades de algunas perovskitas dobles laminares con fórmula LnBaCoO5.50 que presentan una transición metal-aislante cerca de temperatura ambiente. YBaCoO5.50 muestra sucesivas transiciones estructurales y magnéticas que están relacionadas con cambios en el estado de espín. A partir de técnicas de difracción y espectroscopías de rayos-X hemos examinado el papel de los cambios en el estado de espín de los iones Co3+ (en coordinación octaédrica y piramidal) como mecanismo para la transición metal-aislante. La cobaltita de fórmula Ba2Co9O14 presenta una cierta complejidad estructural y propiedades catalíticas y termoeléctricas prometedoras. Hemos encontrado y descrito una fuerte correlación entre el orden magnético singular, los cambios estructurales y la transición aislante-aislante de alta temperatura con cambios del estado del espín en posiciones específicas de los átomos de cobalto durante dicha transición.The work presented in this thesis has been carried out between January of 2011 and December of 2015 at the Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), with the collaboration of the ALBA Synchrotron Light Source (Cerdanyola del Vallès). Cobalt oxides present a plethora of remarkable properties and physical phenomena like giant magnetoresistance, double-exchange, phase separation, spin-state changes, metal-insulator transitions (MIT), high thermoelectric power, oxygen diffusivity, mixed-conduction, charge, spin-state and orbital ordering or superconductivity among others. These properties are interesting not only from a fundamental point of view but also due to their potential applicability in different fields (spintronics, thermoelectric devices, materials for SOFCs, catalyst systems, sensors, etc..). A very remarkable characteristic of cobaltites is the almost unic ability of Co ions to adopt different spin states. This makes that Co oxides have, in comparison with other transition metal oxides, an extra degree of freedom, which favors the spin-lattice coupling and plays a prominent role in the electron mobility, the thermoelectric and catalytic responses or the structural and magnetic stability. In this thesis, we have investigated the influence of spin state instabilities on the structural, electrical and magnetic properties of cobalt oxides with spin-lattice coupling. Four main classes of strongly correlated cobaltites having different crystallographic structures were prepared or fabricated (mainly but not solely) in bulk form: LnCoO3, Ln0.50Sr0.50CoO3, LnBaCoO5.50 and Ba2Co9O14. Structural, electronic, magnetic, magnetostructural and metal-insulator transitions were addressed by means of experiments using synchrotron X-rays and neutron sources. Among them, the ALBA (Barcelona), ESRF (Grenoble), SLS (PSI, Switzerland) and Helmholtz-Zentrum Berlin-BESSY II (HZB, Berlín) synchrotrons, the ILL neutron reactor (Grenoble) and the SINQ (PSI, Switzerland) spallation source, performing Neutron Powder Diffraction (NPD), Synchrotron X-Ray Powder Diffraction (SXRPD), X-ray Absorption and Emission Spectroscopies (XAS and XES), and X-ray Magnetic Circular Dichroism (XMCD). The interest for LnCoO3 arises from the nature of the two stages spin-state (SS) transition and the possible scenarios proposed for the LaCoO3 reference compound: LS→LS+HS→HS or LS→IS→HS. We have combined the analysis of XAS and NPD to understand the influence of the espín configuration on the crystalline structure evolution, and its variation in the phase diagram by increasing the distortion of LnCoO3 compounds. In the case of the low temperature unexpected second magnetic transition in the FM metal Pr0.50Sr0.50CoO3, the resolution of the crystal and magnetic structures we here provide together with the orbital moment characterization have been crucial to understand the mechanism of the magnetostructural transition in this compound. The synthesis of compounds with similar composition has allowed us to draw an overview of the magnetic and electronic properties of the half-doped Ln0.50(Sr, A)0.50CoO3 cobaltites family (A=Ba, Ca). The complex properties of some double-layered LnBaCoO5.50 perovskites presenting a metal-insulator transition close to room temperature were carefully examined. YBaCoO5.50 exhibits successive concomitant structural and magnetic transitions coupled to spin-state changes. The influence of the changes in the spin state of Co3+ ions as the mechanism for the metal-insulator transition has been described for Co atoms in octahedral and pyramidal coordination using X-ray spectroscopies and diffraction techniques. The charge-ordered Ba2Co9O14 cobaltite presents structural complexity and promising catalytic and thermoelectric properties. We have described a close correlation between its singular magnetic order, structural changes and the insulator-insulator transition at high temperature, and the change in the spin-state of specific Co sites at this transition

Simultaneous para-ferrimagnetic, metal-insulator, and orthorhombic-monoclinic transitions in YBaCo2O5.50

Ultrahigh resolution synchrotron x-ray powder diffraction shows up two structural transitions in the layered cobaltite YBaCo2O5.50. The room-temperature orthorhombic structure transforms, on cooling below TMI≃295 K, to monoclinic coinciding with the apparition of a ferromagnetic moment and the occurrence of the metal to insulator transition. On further cooling, the ferromagnetic component disappears and orthorhombic symmetry is recovered

Cosmic acceleration from asymmetric branes

We consider a single 3-brane sitting in between two different five dimensional spacetimes. On each side of the brane, the bulk is a solution to Gauss-Bonnet gravity, although the bare cosmological constant, funda mental Planck scale, and Gauss-Bonnet coupling can differ. This asymmetry leads to weighted junction conditions across the brane and interesting brane cosmology. We focus on two special cases: a generalized Randall-Sundrum model without any Gauss-Bonnet terms, and a stringy model, without any bare cosmological constants, and positive Gauss-Bonnet coupling. Even though we assume there is no vacuum energy on the brane, we find late time de Sitter cosmologies can occur. Remarkably, in certain parameter regions, this acceleration is preceded by a period of matter/radiation domination, with $H^2 \propto \rho$, all the way back to nucleosynthesis.Comment: Version appearing in CQ