Compendio de Historia Universal

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Compendio de Historia Universal

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AMISEC: Leveraging Redundancy and Adaptability to Secure AmI Applications

Security in Ambient Intelligence (AmI) poses too many challenges due to the inherently insecure nature of wireless sensor nodes. However, there are two characteristics of these environments that can be used effectively to prevent, detect, and confine attacks: redundancy and continuous adaptation. In this article we propose a global strategy and a system architecture to cope with security issues in AmI applications at different levels. Unlike in previous approaches, we assume an individual wireless node is vulnerable. We present an agent-based architecture with supporting services that is proven to be adequate to detect and confine common attacks. Decisions at different levels are supported by a trust-based framework with good and bad reputation feedback while maintaining resistance to bad-mouthing attacks. We also propose a set of services that can be used to handle identification, authentication, and authorization in intelligent ambients. The resulting approach takes into account practical issues, such as resource limitation, bandwidth optimization, and scalability

OPENFOAM 3D Modeling of Melt Spinning Process in Non-planar Geometry

Melt spinning is an industrial process used for the production of metallic glasses. It is a rapid solidification process whereby a liquid metal is ejected at high pressure and temperature via a nozzle onto a rotating copper wheel by solidifying in the form of a thin ribbon. In this work, we perform a 3D simulation model to reproduce the melt spinning process to get amorphous magnetic material, starting from an alloy with chemical composition Fe75Si10B15(% at.). A CFD model in the OpenFoam® open source code is proposed and applied, which is based on the Finite Volume Method (FVM) and Volume of Fluid Method (VOF). The entire process without solidification is analyzed simply as a preliminary study of the ejection conditions during the melt, in order to avoid posterior turbulence in the film that would cause irregularities in subsequent stages of solidification. This preliminary analysis aims to study the generation of a regular film of molten material on a rotating cylindrical geometry. In the FVM method the coupled incompressible laminar momentum and continuity equations are solved at each time step on every mesh cell, while in the VOF scheme the fluid properties are weighed average of those of air and molten metal. The complete geometry is discretized in a block-structured mesh of pure hexahedra. The profile and dimensions of the resulting meniscus and ribbon during the transient are in good agreement with our previous numerical results.Fil: Maroni, Adrian Gaston. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; ArgentinaFil: Pagnola, Marcelo Rubén. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; ArgentinaFil: Moya, Javier Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; ArgentinaFil: Malmoria, Mariano Esteban Noe. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; ArgentinaSexto Simposio Nacional en Mecánica de Materiales y Estructuras ContinuasCartagena de IndiasColombiaUniversidad Tecnológica de Bolíva

Bimetallic ag-au nanoparticles inside mesoporous titania thin films: Synthesis by photoreduction and galvanic replacement, and catalytic activity

In this work, the synthesis and catalytic activity of bimetallic Ag–Au nanoparticles (NPs) supported in TiO2 mesoporous thin films (MTFs) are presented. The composite materials were obtained through a two-step procedure, performed at room conditions. In the first step, Ag NPs were grown inside the MTFs by photoreduction. Then, a galvanic replacement reaction with Au was carried out, yielding the bimetallic NPs. The composites were characterized by UV/Vis spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray reflectometry (XRR), which show that the alloyed Ag–Au NPs are present inside the mesopores. Moreover, Ag and Au composition relationship can be controlled by adjusting the reaction times of the photoreduction and galvanic replacement reactions, respectively. Pores remain accessible after NPs synthesis, a feature that ensures their possible applications in any device that requires the contact between the NPs and the medium. Catalytic activity of the composites towards 4-nitrophenol reduction by sodium borohydride was evaluated. Although all the bimetallic systems exhibit improved catalytic properties in comparison with the monometallic Ag composite, the sample with lower Au/Ag relationship is the most effective. For the first time, to the best of our knowledge, bimetallic Au–Ag NPs are encapsulated inside mesoporous TiO2 films, paving the way towards a wide variety of applications.Fil: Coneo Rodríguez, Rusbel. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Troiani, Horacio Esteban. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Comision Nacional de Energía Atómica. Gerencia de Área Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Bariloche). División Dispositivos y Sensores; ArgentinaFil: Moya, Sergio Eduardo. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Electrónica. Laboratorio de Instrumentación y Control; Argentina. CIC biomaGUNE; EspañaFil: Bruno, Mariano Martín. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Angelome, Paula Cecilia. Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología; Argentin

Extreme Floods in Small Mediterranean Catchments: Long-Term Response to Climate Variability and Change

Climate change implies changes in the frequency and magnitude of flood events. The influence of climate variability on flooding was evaluated by an analysis of sedimentary (palaeofloods) and documentary archives. A 500-year palaeoflood record at Montlleó River (657 km2 in catchment area), eastern Spain, revealed up to 31 palaeofloods with a range of discharges of 20–950 m3 s−1, and with at least five floods exceeding 740–950 m3 s−1. This information contrasts with the available gauged flood registers (since year 1971) with an annual maximum daily discharge of 129 m3 s−1. Our palaeoflood dataset indicates flood cluster episodes at (1) 1570–1620, (2) 1775–1795, (3) 1850–1890, and (4) 1920–1969. Flood rich periods 1 and 3 corresponded to cooler than usual (about 0.3 °C and 0.2 °C) climate oscillations, whereas 2 and 4 were characterised by higher inter-annual climatic variability (floods and droughts). This high inter-annual rainfall variability increased over the last 150 years, leading to a reduction of annual maximum flow. Flood quantiles (>50 years) calculated from palaeoflood+gauged data showed 30%–40% higher peak discharges than those using only instrumental records, whereas when increasing the catchment area (1500 km2) the discharge estimation variance decreased to ~15%. The results reflect the higher sensitivity of small catchments to changes on flood magnitude and frequency due to climate variability whereas a larger catchment buffers the response due to the limited extent of convective storms. Our findings show that extended flood records provide robust knowledge about hazardous flooding that can assist in the prioritization of low-regret actions for flood-risk adaptation to climate change

What event-related potentials (ERPs) bring to social neuroscience?

Social cognitive neuroscience is a recent interdisciplinary field that studies the neural basis of the social mind. Event-related potentials (ERPs) provide precise information about the time dynamics of the brain. In this study, we assess the role of ERPs in cognitive neuroscience, particularly in the emerging area of social neuroscience. First, we briefly introduce the technique of ERPs. Subsequently, we describe several ERP components (P1, N1, N170, vertex positive potential, early posterior negativity, N2, P2, P3, N400, N400-like, late positive complex, late positive potential, P600, error-related negativity, feedback error-related negativity, contingent negative variation, readiness potential, lateralized readiness potential, motor potential, re-afferent potential) that assess perceptual, cognitive, and motor processing. Then, we introduce ERP studies in social neuroscience on contextual effects on speech, emotional processing, empathy, and decision making. We provide an outline of ERPs' relevance and applications in the field of social cognitive neuroscience. We also introduce important methodological issues that extend classical ERP research, such as intracranial recordings (iERP) and source location in dense arrays and simultaneous functional magnetic resonance imaging recordings. Further, this review discusses possible caveats of the ERP question assessment on neuroanatomical areas, biophysical origin, and methodological problems, and their relevance to explanatory pluralism and multilevel, contextual, and situated approaches to social neuroscience.Fil: Ibañez, Agustin Mariano. Universidad Diego Portales; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Melloni, Margherita. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Huepe, David. Universidad Diego Portales; ChileFil: Helgiu, Elena. Harvard University; Estados UnidosFil: Rivera Rei, Alvaro. Universidad Diego Portales; ChileFil: Canales Johnson, Andrés. Universidad Diego Portales; ChileFil: Baker, Phil. Universidad Favaloro; ArgentinaFil: Moya, Alvaro. Universidad Favaloro; Argentin

Azospirillum spp. biofertilization and corn, sorghum and wheat grain yield

El escrito muestra evidencias del uso de Azospirillum spp. en la producción de grano de maíz, sorgo y trigo en México. Los ensayos en campo se desarrollaron en dos sitios geográfica y tecnológicamente distintos con semillas inoculadas y sembradas con cepas de A. lipoferum o A. brasilense. Los resultados permiten apreciar una respuesta benéfica de la inoculación sólo para sorgo con cepas de A. brasilense VS-7 o VS-9, debido a que el rendimiento de grano fue significativamente mayor (55 y 49%), que el testigo fertilizado. Este resultado prueba la afinidad existente entre sorgo y A. lipoferum VS-7 ó VS-9 y el uso potencial de la biofertilización en una región con nivel tecnológico-productivo medio.This manuscript argues about the Azospirillum spp. biofertilization profit, through grain yield of corn, sorghum and wheat tilled in Mexico. The assays were development in two different places. The seeds were inoculated with A. lipoferum or A. brasilense strains and later sowed. The results demonstrated a beneficial response to inoculation only for sorghum because of A. lipoferum VS-7 or VS-9 strains effect: the grain yield was significantly greater (55% and 49%) than nitrogen fertilizer effect. This result shown the affinity between sorghum plants and A. lipoferum VS-7 or VS-9 strains and the biofertilization potential use in a Mexico region where the agriculture production development a middle technology.Fil: Rangel Lucio, José Antonio. Instituto Tecnológico de Ciudad Victoria (Tamaulipas, México).Fil: Ramírez Gama, Rosa María. Universidad Nacional Autónoma de México. Facultad de Química.Fil: Cervantes Ortíz, Francisco. Instituto Tecnológico de Roque (Guanajuato, México).Fil: Mendoza Elos, Mariano. Instituto Tecnológico de Roque (Guanajuato, México).Fil: García Moya, Edmundo. Texcoco (México). Colegio de PostgraduadosFil: Rivera Reyes, Guadalupe. Universidad Nacional Autónoma de México. Facultad de Química

Extreme Floods in Small Mediterranean Catchments: Long-Term Response to Climate Variability and Change

: Climate change implies changes in the frequency and magnitude of flood events. The influence of climate variability on flooding was evaluated by an analysis of sedimentary (palaeofloods) and documentary archives. A 500-year palaeoflood record at Montlleó River (657 km2 in catchment area), eastern Spain, revealed up to 31 palaeofloods with a range of discharges of 20-950 m3 s −1 , and with at least five floods exceeding 740-950 m3 s −1 . This information contrasts with the available gauged flood registers (since year 1971) with an annual maximum daily discharge of 129 m3 s −1 . Our palaeoflood dataset indicates flood cluster episodes at (1) 1570-1620, (2) 1775-1795, (3) 1850-1890, and (4) 1920-1969. Flood rich periods 1 and 3 corresponded to cooler than usual (about 0.3 ◦C and 0.2 ◦C) climate oscillations, whereas 2 and 4 were characterised by higher inter-annual climatic variability (floods and droughts). This high inter-annual rainfall variability increased over the last 150 years, leading to a reduction of annual maximum flow. Flood quantiles (>50 years) calculated from palaeoflood+gauged data showed 30%-40% higher peak discharges than those using only instrumental records, whereas when increasing the catchment area (1500 km2 ) the discharge estimation variance decreased to ~15%. The results reflect the higher sensitivity of small catchments to changes on flood magnitude and frequency due to climate variability whereas a larger catchment buffers the response due to the limited extent of convective storms. Our findings show that extended flood records provide robust knowledge about hazardous flooding that can assist in the prioritization of low-regret actions for flood-risk adaptation to climate change

Improving Security for SCADA Sensor Networks with Reputation Systems and Self-Organizing Maps

The reliable operation of modern infrastructures depends on computerized systems and Supervisory Control and Data Acquisition (SCADA) systems, which are also based on the data obtained from sensor networks. The inherent limitations of the sensor devices make them extremely vulnerable to cyberwarfare/cyberterrorism attacks. In this paper, we propose a reputation system enhanced with distributed agents, based on unsupervised learning algorithms (self-organizing maps), in order to achieve fault tolerance and enhanced resistance to previously unknown attacks. This approach has been extensively simulated and compared with previous proposals