1,229 research outputs found

    Sobre la conjetura de secciones en geometría anabeliana

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    ilustraciones, gráficasIn this work, we study and present in detail some ground ideas of anabelian geometry, from its origin in number field and arithmetic results to the statements proposed by Grothendieck, studying theory of fundamental groups in algebraic geometry. We do emphasis in study of section conjecture.En este trabajo estudiamos y presentamos en detalle algunas ideas de geometría anabeliana, desde su origen en teoría de cuerpos y aritmética a los enunciados propuestos Grothendieck, estudiando la teoría de grupos fundamentales en geometría algebraica. Hacemos énfasis en estudiar la conjetura de secciones. (Texto tomado de la fuente).MaestríaMagíster en Ciencias - Matemática

    Compuestos organometálicos en reacciones de acoplamiento deshidrogenante, transformación de dióxido de carbono y otros procesos catalíticos.

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    El objetivo de esta Tesis Doctoral consiste en el empleo de ligandos con diferentes propiedades estereoelectrónicas y su papel en el diseño de complejos organometálicos capaces de activar moléculas a priori inertes (Capítulo 1), de obtener catalíticamente un único producto de manera selectiva (Capítulos 1 y 4) o de detectar y aislar intermedios de reacción cuya naturaleza es elusiva y altamente reactiva (Capítulos 2 y 3). En el capítulo 1 se describe la formación de complejos de Ni(II) estabilizados por un ligando de tipo pinza bis(fosfino)borilo, o PBP, de entre los cuales un complejo de tipo hidruro es capaz de activar dióxido de carbono de forma instantánea a temperatura ambiente. Asimismo, se describe la hidrosililación selectiva de CO2 al nivel de formaldehído (bis(silil)acetal) en presencia del ácido de Lewis tris(pentafluorofenil)borano y silanos como agentes reductores. En el capítulo 2 de esta Tesis Doctoral se describe la síntesis y aislamiento de un complejo de Ni(II) que contiene dos ligandos de tipo borilo, los cuales se orientan en una posición mutuamente trans. La obtención de cristales de esta especie permitió llevar a cabo un detallado análisis estructural, y además se demuestra el papel de estos compuestos como intermedios reactivos en procesos catalíticos de borilación deshidrogenante de estirenos, obteniéndose derivados mono- y di-borilados como productos. En el capítulo 3 se utilizan ligandos del tipo carbeno N-heterocíclico para estabilizar complejos de Pt(II), los cuales se utilizan como ácidos de Lewis para activar silanos. Estudios exploratorios con derivados que contienen el carbeno ItBu condujeron a la utilización de derivados ligeramente menos voluminosos. Para ello se sintetizó el carbeno mixto ItBuiPr, el cual contiene grupos terc-butilo e iso-propilo. Tras evaluar la interacción entre los complejos resultantes de Pt(II) y diversos silanos, se consiguieron aislar varios complejos sigma-silano catiónicos de Pt(II), y su estructura cristalina pudo ser obtenida mediante difracción de rayos X. Además de un detallado análisis estructural, se demostró el papel de estas especies como intermedios reactivos en la formación de enlaces C−Si y/o Pt−Si. De manera adicional, se sintetizaron diferentes complejos de tipo mono y di-deuteruro utilizando diversos ligandos NHC para estudiar su comportamiento como rotores moleculares, en colaboración con los profesores Ulrich Fekl y Robert W. Schurko, de las Universidades de Toronto y Windsor, respectivamente. En el capítulo 4, se emplean algunos de los complejos de Pt(II) que contienen carbenos del tipo ItBu (descritos en el capítulo 3) como catalizadores en procesos de hidrosililación de dióxido de carbono y acoplamiento deshidrogenante de silanos y aminas. En el primer caso, la reducción de CO2 con silanos catalizada por Pt(II) dio como resultado la obtención selectiva de sililformiatos a temperatura ambiente, mientras que en el segundo caso se consiguió la síntesis selectiva de mono- y disilazanos a temperatura ambiente con cargas de catalizador extremadamente bajas, utilizando en varios casos cargas del orden de partes por millón.Premio Extraordinario de Doctorado U

    Diego de Valera y la literatura de mirabilia. El "Liber de Natura Rerum" de Tomás de Cantimpré como fuente de la "Crónica Abreviada".

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    Este trabajo demuestra que una de las fuentes empleadas por Diego de Valera en la primera parte de su "Crónica abreviada de España" conocida también como la "Valeriana" es el "Liber de Natura Rerum" de Tomás de Cantimpré. El cotejo del texto latino con el castellano no deja lugar a dudas

    Signalling Three-Way Intersections: Is Redundancy Better Than Only Mandatory or Prohibitory Signs?

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    This work was supported by the Spanish Government, Ministry of Economy and Competitiveness (PGC2018-095868-B-I00).At intersections, drivers need to infer which ways are allowed by interpreting mandatory and/or prohibitory traffic signs. Time and accuracy in this decision-making process are crucial factors to avoid accidents. Previous studies show that integrating information from prohibitory signs is generally more difficult than from mandatory signs. In Study 1, we compare combined redundant signalling conditions to simple sign conditions at three-way intersections. In Study 2, we carried out a survey among professionals responsible for signposting to test whether common practices are consistent with experimental research. In Study 1, an experimental task was applied (n = 24), and in Study 2, the survey response rate was 17%. These included the main cities in Spain such as Madrid and Barcelona. Study 1 showed that inferences with mandatory signs are faster than those with prohibitory signs, and redundant information is an improvement only on prohibitory signs. In Study 2, prohibitory signs were those most frequently chosen by professionals responsible for signposting. In conclusion, the most used signs, according to the laboratory study, were not the best ones for signposting because the faster responses were obtained for mandatory signs, and in second place for redundant signs.Spanish Government, Ministry of Economy and Competitiveness PGC2018-095868-B-I0

    Inferences from the negation of counterfactual and semifactual conditionals

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    Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work was supported by the Spanish Government, Ministry of Economy and Competitiveness [PGC2018-095868-B-I00].Our goal was to study how people understand the negation of counterfactuals (such as “Antonio denied/said that it is false that if Messi had played, then Barcelona would have won”) and semifactuals (such as “Antonio denied that even if Messi had played, Barcelona would have won”). Previous studies have shown that participants negated basic conditionals using small-scope interpretations by endorsing a new conditional with the negated consequent, but also by making large-scope interpretations, endorsing a conjunction with the negated consequent. Three experiments showed that when participants were asked whether the negation of a counterfactual (Experiments 1 and 2) or semifactual (Experiment 3) conditional was followed by a new conditional, they made a small-scope interpretation, endorsing the same conditional with the negated consequent (e.g., “if/even if Messi had played, Barcelona would not have won”). However, they also accepted the conditional with the negated antecedent for semifactuals (e.g., “even if Messi had not played, Barcelona would have won”). When participants were asked whether the negation of a counterfactual or semifactual conditional is followed by a conjunction, they endorsed the conjunction with both the negated antecedent and the consequent (e.g., “Messi did not play and Barcelona did not win”), but again they accepted the conjunction with the negated antecedent only for semifactuals (e.g., “Messi did not play and Barcelona did win”). These results have implications for the main theories of reasoning.CRUE-CSIC agreementSpringer NatureSpanish Government, Ministry of Economy and Competitiveness PGC2018-095868-B-I0

    Efficient DMA transfers management on embedded Linux PSoC for Deep-Learning gestures recognition: Using Dynamic Vision Sensor and NullHop one-layer CNN accelerator to play RoShamBo

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    This demonstration shows a Dynamic Vision Sensor able to capture visual motion at a speed equivalent to a highspeed camera (20k fps). The collected visual information is presented as normalized histogram to a CNN accelerator hardware, called NullHop, that is able to process a pre-trained CNN to play Roshambo against a human. The CNN designed for this purpose consist of 5 convolutional layers and a fully connected layer. The latency for processing one histogram is 8ms. NullHop is deployed on the FPGA fabric of a PSoC from Xilinx, the Zynq 7100, which is based on a dual-core ARM computer and a Kintex-7 with 444K logic cells, integrated in the same chip. ARM computer is running Linux and a specific C++ controller is running the whole demo. This controller runs at user space in order to extract the maximum throughput thanks to an efficient use of the AXIStream, based of DMA transfers. This short delay needed to process one visual histogram, allows us to average several consecutive classification outputs. Therefore, it provides the best estimation of the symbol that the user presents to the visual sensor. This output is then mapped to present the winner symbol within the 60ms latency that the brain considers acceptable before thinking that there is a trick.Ministerio de Economía y Competitividad TEC2016-77785-

    Los estudios de Filología Moderna. Alemán.

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    Panorama sobre los estudios de Filología Alemana en la Facultad de Filosofía y Letras de Madrid durante los años 30. Se pone énfasis en el papel desempeñado por el lector Georg Sachs en el desarrollo de estos estudio

    Auditory hindsight bias in school-age children

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    We report two experiments investigating hindsight bias in children, focusing on a rarely studied age range of 8–13 years. In Experiment 1, we asked children to complete both an auditory hindsight task and a visual hindsight task. Children exhibited hindsight bias in both tasks, and the bias decreased with age. In Experiment 2, we further explored children ‘s auditory hindsight bias by contrasting performance in hypothetical and memory designs (which previous research with adults had found to involve different mechanisms—fluency vs. memory reconstruction). Children exhibited auditory hindsight bias in both tasks, but only in the hypothetical design was the bias magnitude modulated by a priming manipulation designed to increase fluency, replicating and extending the pattern found in adults to children.Spanish Government PGC2018-095868-B-I00Universidad de Granada/CBU
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