267 research outputs found

    Enhanced magneto-optical Kerr effect in oxidized Co thin films

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    We have studied the structural and magneto-optical properties of postdeposition oxidized Co thin films. The oxidization process leads to the formation of a double-layered structure of fcc Co3O4 on top of metallic Co. The magneto-optical Kerr effect (MOKE), measured in the range 0.8 eV ⩽ EPh ⩽ 5.5 eV reveals characteristic dependencies of the MOKE spectra on annealing temperature and time. In particular, we observe resonance-type enhancements of the Kerr effects by up to a factor of 10 compared with unannealed metallic Co. The experimental data are quantitatively reproduced by bilayer optical stack calculations.One of the authors ~B.R.! has been gratefully supported by means of the Deutsche Forschungsgemeinschaft. One of the authors ~G.A.! thanks the Ministerio De Educacion y Ciencia ~Spain! for financial support.Peer reviewe

    Geometry of Middle to Late Triassic extensional deformation pattern in the Cordillera del Viento (Southern Central Andes): A combined field and geophysical study

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    Combined field and gravimetric-magnetic data reveal a complex pattern of extensional structures superimposed to the late Carboniferous – Early Permian Gondwanan orogen at the inner sectors of the Southern Central Andes, in the westernmost part of the Chos Malal fold and thrust belt at the cordillera del Viento area. W-NW, NW basement structures of regional significance, segmented by minor NE structures are bounding Late Triassic depocenters and structural highs corresponding to the cordillera del Viento rifting, equivalent to the Precuyo cycle. A pattern of roughly N-S trending structures recognized in the field associated with Andean thrusts do not show evidences of previ­ous structural controls, as they cut the magnetic anomalies. Field observations show that W-NW, NW and NE normal structures control changes in Late Triassic sedimentary thicknesses and are associated with synextensional geometries. Our model indicates that Late Triassic rifting in the area would have had a regional W-NW to NW trend being segmented by minor NE structures. Both sets were reactivated dur­ing Andean times, acting W-NW and NW structures as transfer zones between decoupled contractional panels and NE structures as frontal contractional structures. N-S contractional structures did not respect rifting architecture cutting through the depocenters and occasionaly exhuming synextensional geometries.La combinacion de datos de campo, junto con magnéticos y gravimétricos, revelan un patrón complejo de estructuras sobreimpuestas al orógeno gondwánico (Carbonífero superior– Pérmico) en el sector interno de la faja plegada y corrida de los Andes Centrales australes, en el área de la cordillera del Viento. Estructuras de basamento W-NW, NW de significancia regional, segmentadas por estruturas menores NE están limitando depocentros y altos estructurales correspondientes al rifting del Triásico Superior de la cordillera del Viento, equivalente de las unidades del ciclo Precuyo. En el campo se reconoce además un patrón de estructuras de rumbo N, asociadas a fallas andinas que no muestran evidencias de un control estrutural previo, ya que las anomalías magnéticas están cortadas por éstas. Las observaciones de campo demuestran que tanto las estructuras W-NW y NW como las NE controlan cambios de espesor de los sedimentos del Triásico Superior y se asocian a geometrías sinextensionales. El modelo propuesto indica que el rifting del Triásico Superior podría haber tenido una geometría elongada según el patrón de estructuras identificadas W-NW a NW, segmentado por estructuras menores NE. Ambas muestran reactivación durante tiempos andinos, las primeras actuando como zonas de transferencia entre sectores que muestran diferentes grados y mecánicas de contracción y las últimas como estructuras frontales contraccionales. Las estructuras contraccionales de orientación N-S no respetan la arquitectura del rift triásico, cortando los depocentros y eventualmente exhumando geometrías sinextensionales

    Tectonosedimentary evolution of the Coastal Cordillera and Central Depression of south-Central Chile (36°30′-42°S)

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    The forearc of south-central Chile (36°30′-42°S) is characterized by the presence of a Coastal Cordillera and a low lying area known as the Central Depression. The origin of these morphostructural units has been largely debated. They have been ascribed to different ages between the Cretaceous and the Pliocene, and tectonic causes that involve extensional or contractional deformation and have been related to Andean evolution or accretionary processes in the forearc. To investigate the geologic evolution of the Coastal Cordillera and Central Depression in the cited area, we based on stratigraphy, sedimentology, geochronology (U[sbnd]Pb, LA-ICP-MS), structural geology, and geomorphology. Our studies, which are based on our own data and a thorough bibliographic review, indicate the following sequence of events in the tectono-sedimentary evolution of the forearc of south-central Chile during the late Cenozoic. The area was subjected to extensional tectonics caused by slab rollback during the Oligocene-early Miocene, resulting in the genesis of a series of basins filled with volcanic, continental, and marine deposits that extended from the present Chilean coast to the retroac. The extensional basins were tectonically inverted during the late Early-Late Miocene, and most of the forearc became a positive relief that was subjected to fluvial erosion. The West Andean Thrust, a major reverse west verging fault in the limit between the Central Depression and the Andean Cordillera, caused significant uplift of the western flank of the Andes. This triggered flexural subsidence and the accumulation of coarse-grained deposits in the forearc during the Pliocene-Pleistocene. The sudden increase of sediment flux to the trench during this period caused a change from non-accretion or subduction erosion to accretion in the margin of south-central Chile. Progressive growth of the accretionary wedge gave birth to a forearc high, the Coastal Cordillera, which was uplifted in the last 2 Ma. Some forearc areas placed above subducted oceanic fracture zones did not experience uplift during this period due to the significant transport of fluid that inhibited the deformation of the accretionary wedge. Our studies show that the late Cenozoic tectono-sedimentary evolution of the forearc in the study area is complex and involves different processes related to Andean evolution in the first stage and accretionary processes acting exclusively in the forearc in a second stage. The Coastal Cordillera and the Central Depression of south-central Chile were developed in the last 2 Ma and are much younger than classically considered.Fil: Encinas, A.. Universidad de Concepción; ChileFil: Sagripanti, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Rodríguez, M.P.. Universidad de Atacama.; ChileFil: Orts, Darío Leandro. Universidad Nacional de Río Negro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Anavalón, A.. Universidad de Concepción; ChileFil: Giroux, P.. Universidad de Concepción; ChileFil: Otero, J.. Universidad Austral de Chile; ChileFil: Echaurren Gonzalez, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Zambrano, P.. Universidad Andrés Bello; ChileFil: Valencia, V.. Washington State University; Estados Unido

    A Novel Anti-Influenza Copper Oxide Containing Respiratory Face Mask

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    Protective respiratory face masks protect the nose and mouth of the wearer from vapor drops carrying viruses or other infectious pathogens. However, incorrect use and disposal may actually increase the risk of pathogen transmission, rather than reduce it, especially when masks are used by non-professionals such as the lay public. Copper oxide displays potent antiviral properties. A platform technology has been developed that permanently introduces copper oxide into polymeric materials, conferring them with potent biocidal properties.. The copper oxide containing masks successfully passed Bacterial Filtration Efficacy, Differential Pressure, Latex Particle Challenge, and Resistance to Penetration by Synthetic Blood tests designed to test the filtration properties of face masks in accordance with the European EN 14683:2005 and NIOSH N95 standards.Impregnation of copper oxide into respiratory protective face masks endows them with potent anti-influenza biocidal properties without altering their physical barrier properties. The use of biocidal masks may significantly reduce the risk of hand or environmental contamination, and thereby subsequent infection, due to improper handling and disposal of the masks

    Climacteric Lowers Plasma Levels of Platelet-Derived Microparticles: A Pilot Study in Pre-versus Postmenopausal Women

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    Background: Climacteric increases the risk of thrombotic events by alteration of plasmatic coagulation. Up to now, less is known about changes in platelet-(PMP) and endothelial cell-derived microparticles (EMP). Methods: In this prospective study, plasma levels of microparticles (MP) were compared in 21 premenopausal and 19 postmenopausal women. Results: No altered numbers of total MP or EMP were measured within the study groups. However, the plasma values of CD61-exposing MP from platelets/megakaryocytes were higher in premenopausal women (5,364 x 10(6)/l, range 4,384-17,167) as compared to postmenopausal women (3,808 x 10(6)/l, range 2,009-8,850; p = 0.020). This differentiation was also significant for the subgroup of premenopausal women without hormonal contraceptives (5,364 x 10(6)/l, range 4,223-15,916; p = 0.047; n = 15). Furthermore, in premenopausal women, higher plasma levels of PMP exposing CD62P were also present as compared to postmenopausal women (288 x 10(6)/l, range 139-462, vs. 121 x 10(6)/l, range 74-284; p = 0.024). This difference was also true for CD63+ PMP levels (281 x 10(6)/l, range 182-551, vs. 137 x 10(6)/l, range 64-432; p = 0.015). Conclusion: Climacteric lowers the level of PMP but has no impact on the number of EMP in women. These data suggest that PMP and EMP do not play a significant role in enhancing the risk of thrombotic events in healthy, postmenopausal women. Copyright (C) 2012 S. Karger AG, Base

    Quality of medication use in primary care - mapping the problem, working to a solution: a systematic review of the literature

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    Background: The UK, USA and the World Health Organization have identified improved patient safety in healthcare as a priority. Medication error has been identified as one of the most frequent forms of medical error and is associated with significant medical harm. Errors are the result of the systems that produce them. In industrial settings, a range of systematic techniques have been designed to reduce error and waste. The first stage of these processes is to map out the whole system and its reliability at each stage. However, to date, studies of medication error and solutions have concentrated on individual parts of the whole system. In this paper we wished to conduct a systematic review of the literature, in order to map out the medication system with its associated errors and failures in quality, to assess the strength of the evidence and to use approaches from quality management to identify ways in which the system could be made safer. Methods: We mapped out the medicines management system in primary care in the UK. We conducted a systematic literature review in order to refine our map of the system and to establish the quality of the research and reliability of the system. Results: The map demonstrated that the proportion of errors in the management system for medicines in primary care is very high. Several stages of the process had error rates of 50% or more: repeat prescribing reviews, interface prescribing and communication and patient adherence. When including the efficacy of the medicine in the system, the available evidence suggested that only between 4% and 21% of patients achieved the optimum benefit from their medication. Whilst there were some limitations in the evidence base, including the error rate measurement and the sampling strategies employed, there was sufficient information to indicate the ways in which the system could be improved, using management approaches. The first step to improving the overall quality would be routine monitoring of adherence, clinical effectiveness and hospital admissions. Conclusion: By adopting the whole system approach from a management perspective we have found where failures in quality occur in medication use in primary care in the UK, and where weaknesses occur in the associated evidence base. Quality management approaches have allowed us to develop a coherent change and research agenda in order to tackle these, so far, fairly intractable problems

    Evaluation of baculoviruses as gene therapy vectors for brain cancer

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    We aimed to assess the potential of baculoviral vectors (BV) for brain cancer gene therapy. We compared them with adenoviral vectors (AdV), which are used in neuro-oncology, but for which there is pre-existing immunity. We constructed BVs and AdVs encoding fluorescent reporter proteins and evaluated their transduction efficiency in glioma cells and astrocytes. Naïve and glioma-bearing mice were intracranially injected with BVs to assess transduction and neuropathology. Transgene expression was also assessed in the brain of BV-preimmunized mice. While the expression of BVs was weaker than AdVs in murine and human glioma cell lines, BV-mediated transgene expression in patient-derived glioma cells was similar to AdV-mediated transduction and showed strong correlation with clathrin expression, a protein that interacts with the baculovirus glycoprotein GP64, mediating BV endocytosis. BVs efficiently transduced normal and neoplastic astrocytes in vivo, without apparent neurotoxicity. BV-mediated transgene expression was stable for at least 21 days in the brain of naïve mice, but it was significantly reduced after 7 days in mice systemically preimmunized with BVs. Our findings indicate that BVs efficiently transduce glioma cells and astrocytes without apparent neurotoxicity. Since humans do not present pre-existing immunity against BVs, these vectors may constitute a valuable tool for the delivery of therapeutic genes into the brain.Instituto de Biotecnología y Biología Molecula

    Can Interactions between Timing of Vaccine-Altered Influenza Pandemic Waves and Seasonality in Influenza Complications Lead to More Severe Outcomes?

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    Vaccination can delay the peak of a pandemic influenza wave by reducing the number of individuals initially susceptible to influenza infection. Emerging evidence indicates that susceptibility to severe secondary bacterial infections following a primary influenza infection may vary seasonally, with peak susceptibility occurring in winter. Taken together, these two observations suggest that vaccinating to prevent a fall pandemic wave might delay it long enough to inadvertently increase influenza infections in winter, when primary influenza infection is more likely to cause severe outcomes. This could potentially cause a net increase in severe outcomes. Most pandemic models implicitly assume that the probability of severe outcomes does not vary seasonally and hence cannot capture this effect. Here we show that the probability of intensive care unit (ICU) admission per influenza infection in the 2009 H1N1 pandemic followed a seasonal pattern. We combine this with an influenza transmission model to investigate conditions under which a vaccination program could inadvertently shift influenza susceptibility to months where the risk of ICU admission due to influenza is higher. We find that vaccination in advance of a fall pandemic wave can actually increase the number of ICU admissions in situations where antigenic drift is sufficiently rapid or where importation of a cross-reactive strain is possible. Moreover, this effect is stronger for vaccination programs that prevent more primary influenza infections. Sensitivity analysis indicates several mechanisms that may cause this effect. We also find that the predicted number of ICU admissions changes dramatically depending on whether the probability of ICU admission varies seasonally, or whether it is held constant. These results suggest that pandemic planning should explore the potential interactions between seasonally varying susceptibility to severe influenza outcomes and the timing of vaccine-altered pandemic influenza waves

    Escuela de ayudantes alumnos: arte y parte del ayudante alumno como tutor de pares

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    La preocupación por cómo y para qué enseñar y aprender se muestra como una constante a lo largo del tiempo; ello invita a plantear alternativas innovadoras. Las experiencias en Escuelas de Ayudantes resultan alentadoras en capacitación docente; inserción en equipos docentes; mejoramiento en la formación de grado; integración transversal y vertical; reflexión crítica; apropiación de conocimientos; etc. Dentro del contexto de las “prácticas de docencia compartida”, precisamente le cabe a los alumnos compartir los procesos de aprendizaje entre ellos y los docentes. Objetivo: implementar un sistema de Tutorías de Pares en Histología en las dimensiones pedagógica y disciplinar. Participan del trabajo: docentes, no docente, asesora pedagógica y alumnos. Se preveen actividades áulicas y de Formación y Capacitación Pedagógica y Científica. Se aspira a estimular el pensamiento reflexivo entre el contenido teórico y la práctica profesional; generar un espacio de discusión y formulación de propuestas orientadas al mejoramiento del aprendizaje, propiciar el desarrollo de habilidades; capacitar al aspirante en actividades de docencia; ofrecer un ámbito para el desarrollo de actividades de investigación propiamente dichas y como saber científico aplicado a la docencia de grado; fomentar la habilidad para desempeñar tareas en equipo; favorecer la formación de recursos humanos desde el grado; abordar la problemática de deserción estudiantil. PIIMEG SECyTUNRC( 2011-2012).Eje temático 2: Los cambios e innovaciones en los procesos de formación a - Alternativas didácticas y experiencias de renovación de la enseñanzaFacultad de Ciencias Agrarias y Forestale
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