1,545 research outputs found
Internet y África: de la brecha a la esperanza digital. Redes, libertades y comunicación
With a critical and comparative perspective, the article outlines the digital universe reality in Africa, taking into account regional differences. Descriptively, we are interested in issues such as Internet access situation, policies and existing regulatory infrastructure, the digital economy, the impact of new media, e-government initiatives and digital citizen participation, together with some aspects of the cultural colonization that may occur as a result of the universalization of a clearly westernized Internet. Con una mirada crítica y comparativa se esboza la realidad del universo digital en África, teniendo en cuenta las diferencias regionales existentes. De modo descriptivo, nos interesamos por cuestiones como la situación del acceso a Internet, las políticas de infraestructuras y regulatorias existentes, la economía digital, el impacto de los nuevos medios, las iniciativas de gobierno electrónico y participación ciudadana digital, y algunos aspectos de la colonización cultural que se puede producir a cuentas de una red claramente occidentalizada
Factores determinantes del spread de los bonos Soberanos: Perú, 2000-2018
El artículo infiere cuáles fueron los factores que incidieron en la determinación del spread soberano del Perú durante el 2000-2018. La investigación asumió el diseño explicativo-retrospectivo mediante la aplicación de modelación y estimación econométrica a través de datos panel. Metodológicamente se utilizó la regresión agrupada con los modelos de efectos aleatorios y de efectos fijos, finalizando con la aplicación de las pruebas de Hausman, Wald y Wooldridge. Los resultados demuestran que el modelo que mejor se ajusta a la estimación del spread de los bonos soberanos del Perú, Chile y Colombia, es el modelo de datos Panel de Efectos Fijos, cuyas doce variables explicativas planteadas en el modelo, tan solo cuatro tuvieron resultados significativos y relevantes en el análisis estático y cinco variables en el análisis dinámico. Las variables que impactan positivamente en el spread de los bonos soberanos de los tres países son: la inflación, la Dummy de crisis financiera y el primer rezago de la variable endógena, mientras que las que impactan negativamente son: la razón Inversión Total a PBI y la Razón Saldo en la Cuenta Corriente a PBI
Programación didáctica módulo Aplicaciones Web. 2º Curso del Ciclo Formativo de Grado Medio de Formación Profesional. Sistema microinformáticos y redes
Máster Universitario en Formación del Profesorado de ESO, Bachillerato, Formación Profesional y Enseñanza de Idiomas. Especialidad en Tecnología (M090
Los sulfuros masivos volcanogénicos de la Cuenca Lancones (Piura-Perú)
The Lancones basin is located on the north west coastal belt area of Peru, in the Department of Piura. It isbordered to the west by the Palaeozoic Amotapes coastal massif and to the east by the Western Andespre-mountain range region. This basin extends to Ecuador, where it is called Celica basin.The Lancones basin contains arc-related felsic and mafic volcanic rocks, which make it an excellent targetfor exploration for volcanogenic massive sulphide (VMS) deposits in Peru. Actually the Lancones basinhosts the Tambogrande VMS group of deposits, which constitute the most advanced VMS project in Peru.This group consists of three world-class massive sulphide deposits TG1, TG3 and B5.The Lancones basin is part of a first-order extensive rift, in which tholeiitic oceanic-arc crust was generated.This extensional basin developed between the late Jurassic and the early Cretaceous period. The breakupof Laurasia and Gondwana, which began in the middle Jurassic, resulted in the north-west movement ofwhat is presently the South American continent. The rift formed along a subduction zone on the westernside of this continent.The stratigraphy of the submarine volcanic sequences is composed of a basal formation, the Basal VolcanicGroup or GBV, which is disconformably overlain by a volcano-sedimentary formation, the VolcanicSedimentary Group or GVS. These two formations contain two distinct metallogenic suites within theLancones basin. Each is distinguished by specific lithogeochemical, petrographic and mineral attributes,age determinations and VMS deposit types.The pre-Albian mafic bimodal GBV contains high grade, large tonnage Cu-Zn type VMS deposits(Tambogrande type) associated to dacitic domes formed in second – or third-order extensional basins. Themiddle to upper Albian GVS contains low tonnage Zn-Pb-Cu type VMS mineralizations (Kuroko type).These are associated with felsic sequences of rhyolitic to dacitic composition, associated with a felsicdominatedarc setting. The rocks of the GBV, which contain the polymetallic Tambogrande deposits, aretholeiitic. The rocks of GVS are mainly transitional between calc-alkaline and tholeiitic
Considerations on the physical and mechanical properties of lime-stabilized rammed earth walls and their evaluation by ultrasonic pulse velocity testing
This study examines the influence of moulding moisture content on the compressive strength, dry density and porosity of a rammed earth wall, using ultrasound as a complementary technique. Non-parametric and multivariate statistical techniques were applied to analyse the behaviour of variables with a sufficiently large population. The statistical analysis demonstrated that excessive or insufficient moulding moisture content directly determines the physical-mechanical properties of such walls. Ultrasound was confirmed as a valid technique for assessing the quality of a wall, since its response, albeit with certain limitations, was consistent with physical-mechanical properties
Los efectos nocivos de la investigación social analizados con la Declaración Universal sobre Bioética y Derechos Humanos: Resultados de una encuesta nacional a científicos
Els riscos i danys d'una recerca sol ser un tema discutit en la recerca social en salut, pel fet que s'arriben a minimitzar, negar la seva existència, o no comunicar als participants. La reducció dels efectes nocius s'estipula en l'article 4 de la Declaració Universal sobre Bioètica i Drets Humans, però aquesta referència sembla no al·ludir directament a les ciències socials. Objectius. 1) comprendre els efectes nocius derivats de la recerca social i 2) descriure l'aplicació de l'article 4 de la Declaració, específicament en la reducció dels efectes nocius en els participants en aquest camp de la ciència. Mètode. Apliquem una enquesta a investigadors socials, els qui van respondre un qüestionari electrònic que indagava l'opinió i experiència en algunes de les pràctiques ètiques en els estudis socials. Resultats. Indiquen que els efectes nocius es plantegen com a probabilitat de repercussions de certes accions i decisions de l'investigador; confirma riscos com el mal ús i/o la manipulació de la informació, la generació de falses expectatives en els participants, la invasió dels seus espais i de la seva intimitat. Els danys van ser la revelació de la identitat, la violació dels drets i la generació d'estigma i prejudicis; aporta un altre tipus d'efectes nocius com els interessos propis de l'investigador o de la seva institució. Discussió. Els investigadors socials sí que apliquen l'article 4 de la Declaració, no obstant això, es qüestionen una sèrie d'aspectes del context social i cultural implicat en les repercussions ètiques.Risks and harms comprise a controversial topic in health sciences social research: they are minimised, denied, or not communicated to study participants. Article 4 of the UNESCO Universal Declaration on Bioethics and Human Rights stipulates the need to minimise harm, but this provision does not appear to refer directly to social sciences. Objectives: 1) to understand the harmful effects in social research; and 2) to describe the application of Article 4 to harm reduction in this field of research. Methods: We conducted an internet-based survey with social research investigators, asking about their experience and opinions regarding ethical practices in social research studies. Results: Respondents indicated that harmful effects were considered in terms of the repercussions of certain actions and decisions of the investigator, confirms risks such as the misuse and/or manipulation of information, the generation of false expectations of participants, the invasion of their space and privacy. The harms were disclosure of identity, violation of rights and the generation of stigma and prejudice; it brings in other types of harmful effects such as the self-interest of the researcher or his/her institution. Discussion: Social researchers observe Article 4, but this study questions aspects of the social and cultural context and their ethical repercussions.Los riesgos y daños de una investigación suele ser un tema discutido en la investigación social en salud, debido a que se llegan a minimizar, negar su existencia, no comunicar a los participantes. La reducción de los efectos nocivos se estipula el artículo 4 de la Declaración Universal sobre Bioética y Derechos Humanos, pero esta referencia parece no aludir directamente a las ciencias sociales. Objetivos. 1) comprender los efectos nocivos derivados de la investigación de social y 2) describir la aplicación del artículo 4 de la Declaración, específicamente en la reducción de los efectos nocivos en los participantes en este campo de la ciencia. Método. Aplicamos una encuesta a investigadores sociales, quienes respondieron un cuestionario electrónico que indagaba la opinión y experiencia en algunas las prácticas éticas en los estudios sociales. Resultados. Indican que los efectos nocivos se plantean como probabilidad de repercusiones de ciertas acciones y decisiones del investigador; confirma riesgos como el mal uso y/o la manipulación de la información, la generación de falsas expectativas en los participantes, la invasión de sus espacios y de su intimidad. Los daños fueron la revelación de la identidad, la violación de los derechos y la generación de estigma y prejuicios; aporta otro tipo de efectos nocivos como los intereses propios del investigador o de su institución. Discusión. Los investigadores sociales sí aplican el artículo 4 de la Declaración, sin embargo, se cuestionan una serie de aspectos del contexto social y cultural implicado en las repercusiones éticas
Plasmonic Nanoparticles as Light-Harvesting Enhancers in Perovskite Solar Cells: A User’s Guide
In this Perspective we discuss the implications of employing metal particles of different shape, size, and composition as absorption enhancers in methylammonium lead iodide perovskite solar cells, with the aim of establishing some guidelines for the future development of plasmonic resonance-based photovoltaic devices. Hybrid perovskites present an extraordinarily high absorption coefficient which, as we show here, makes it difficult to extrapolate concepts and designs that are applied to other solution-processed photovoltaic materials. In addition, the variability of the optical constants attained from perovskite films of seemingly similar composition further complicates the analysis. We demonstrate that, by means of rigorous design, it is possible to provide a realistic prediction of the magnitude of the absorption enhancement that can be reached for perovskite films embedding metal particles. On the basis of this, we foresee that localized surface plasmon effects will provide a means to attain highly efficient perovskite solar cells using films that are thinner than those usually employed, hence facilitating collection of photocarriers and significantly reducing the amount of potentially toxic lead present in the device.European Union 307081Ministerio de Economía y Competitividad MAT2011-23593, MAT2014-54852-
Absorption enhancement in methylammonium lead iodide perovskite solar cells with embedded arrays of dielectric particles
In the field of hybrid organic-inorganic perovskite based photovoltaics, there is a growing interest in the exploration of novel and smarter ways to improve the cells light harvesting efficiency at targeted wavelength ranges within the minimum volume possible, as well as in the development of colored and/or semitransparent devices that could pave the way both to their architectonic integration and to their use in the flowering field of tandem solar cells. The work herein presented targets these different goals by means of the theoretical optimization of the optical design of standard opaque and semitransparent perovskite solar cells. In order to do so, we focus on the effect of harmless, compatible and commercially available dielectric inclusions within the absorbing material, methylammonium lead iodide (MAPI). Following a gradual and systematic process of analysis, we are capable of identifying the appearance of collective and hybrid (both localized and extended) photonic resonances which allow to significantly improve light harvesting and thus the overall efficiency of the standard device by above 10% with respect to the reference value while keeping the semiconductor film thickness to a minimum. We believe our results will be particularly relevant in the promising field of perovskite solar cell based tandem photovoltaic devices, which has posed new challenges to the solar energy community in order to maximize the performance of semitransparent cells, but also for applications focusing on architectonic integration.European Union 307081Ministerio de Economía y Competitividad MAT2014-54852-R, MAT2017-88584-
Deciphering GRINA/Lifeguard1: Nuclear Location, Ca2+ Homeostasis and Vesicle Transport
The Glutamate Receptor Ionotropic NMDA-Associated Protein 1 (GRINA) belongs to the Lifeguard family and is involved in calcium homeostasis, which governs key processes, such as cell survival or the release of neurotransmitters. GRINA is mainly associated with membranes of the endoplasmic reticulum, Golgi, endosome, and the cell surface, but its presence in the nucleus has not been explained yet. Here we dissect, with the help of different software tools, the potential roles of GRINA in the cell and how they may be altered in diseases, such as schizophrenia or celiac disease. We describe for the first time that the cytoplasmic N-terminal half of GRINA (which spans a Proline-rich domain) contains a potential DNA-binding sequence, in addition to cleavage target sites and probable PY-nuclear localization sequences, that may enable it to be released from the rest of the protein and enter the nucleus under suitable conditions, where it could participate in the transcription, alternative splicing, and mRNA export of a subset of genes likely involved in lipid and sterol synthesis, ribosome biogenesis, or cell cycle progression. To support these findings, we include additional evidence based on an exhaustive review of the literature and our preliminary data of the protein–protein interaction network of GRINA
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