347 research outputs found

    Direction Detector on an Excitable Field: Field Computation with Coincidence Detection

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    Living organisms process information without any central control unit and without any ruling clock. We have been studying a novel computational strategy that uses a geometrically arranged excitable field, i.e., "field computation." As an extension of this research, in the present article we report the construction of a "direction detector" on an excitable field. Using a numerical simulation, we show that the direction of a input source signal can be detected by applying the characteristic as a "coincidence detector" embedded on an excitable field. In addition, we show that this direction detection actually works in an experiment using an excitable chemical system. These results are discussed in relation to the future development of "field computation."Comment: 6 pages, 3 figure

    Variation of applied field angular dependence of critical current density in YBCO thin films against deposition temperature and composition

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    AbstractFor the magnetic flux pinning in YBa2Cu3Oy (YBCO) thin films, artificial pinning centers (APC) like BaZrO3 and BaSnO3 nanorods act effectively when magnetic fields are applied parallel to the c-axis of the YBCO thin films. However, it is necessary that APC exist into a three dimentional shape and random distribution in order to enhance Jc against all angle range of applied magnetic fields. In this study, we reported YBCO thin films with low anisotropy of Jc against the magnetic field applied angle. As a result, using off-stoichiometric target composition of Y: Ba: Cu = 1: 2: 3.4 and high substrate temperatures, the YBCO thin films which were prepared by pulsed laser deposition method at more than 890°C showed low anisotropic Jc, since the films included pinning centers acting against wide angle range of applied field

    Molecular Beam Epitaxy and p-type Doping of ZnMgSTe Quaternary Alloys

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    ZnS-based ZnMgSTe quaternary alloy layers have been grown by molecular beam epitaxy. The bandgap of ZnMgSTe has been estimated from the reflectance spectra, and it was found that it increases with increasing Mg content, while it decreases with increasing Te content. Nitrogen acceptor doping to Zn1−xMgxS1−yTey layers has also been investigated. The layers with Te content y>0.1 were found to be p-type, and the layer with the larger Te content exhibited lower resistivity. From these results, it seems that the ZnMgSTe quaternary alloy with appropriate composition possesses both a wide bandgap and p-type conductivity

    Análisis de la heurística en la contratación empresarial a través de una cartera de derivados reales

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    Departing from the notion that labour legislation should be founded in the generation of job stability a model for recruitment is presented in which the employer is likened to the holder of an investment portfolio containing two real derivatives – swap or the option of sale. This model allows us on one hand to analyze sensitivity to the variables that are at play in an employment contract and, on the other, look at the effects that the most recent reforms in Spanish labour laws have had on contracting decisions made by employers. The results are clear: social security benefits are shown to be the most sensitive variable on the work contract, and applying the changes proposed in the latest labour reforms, this effect is upheld. The study concludes that reducing the costs of dismissal does not increase the likelihood of employers’ taking on new staff.Dada la situación actual y partiendo del supuesto que como herramienta para una correcta política de empleo la legislación laboral debe sentar las bases sólidas para que en el momento de recuperación económica se generen puestos de trabajo estables, se presenta un modelo de simulación de contratación que nos va a permitir un análisis de sensibilidad de las distintas variables a tener en cuenta en una regulación del mercado laboral. El modelo consiste en asimilar el comportamiento del empresario al del propietario de una cartera de inversión compuesta por dos derivados reales, un swap y una opción de venta americana. Este modelo nos permite, por un lado, hacer un análisis de sensibilidad de las diferentes variables que intervienen en la contratación, y, por otro lado, analizar los efectos que la última reforma laboral española tiene sobre la decisión de contratar del empresario. Los resultados son claros, la variable que más sensibilidad presenta sobre la contratación es la cuota patronal de la seguridad social, y aplicando los cambios propuestos en esta última reforma laboral, se concretan estos efectos y también se concluye que la reducción de los costes de despido no acelera la decisión de contratar.Dada a situação atual e partindo do suposto que como ferramenta para uma correta política de emprego, a legislação laboral deve instituir as bases sólidas para que, no momento da recuperação econômica, se gerem postos de trabalho estáveis, se apresentem um modelo de simulação de contratação que nos permitirá uma análise de sensibilidade das diferentes variáveis a considerar em uma regulação do mercado laboral. O modelo consiste em assimilar o comportamento do empresário ao do proprietário de uma carteira de investimento composto por dois derivados reais, um swap e uma opção de venda americana. Esse modelo nos permite, por um lado, fazer uma análise de sensibilidade das diferentes variáveis que intervêm na contratação e, por outro lado, analisar os efeitos que a última reforma laboral espanhola tem sobre a decisão de contratar do empresário. Os resultados são claros, a variável que mais sensibilidade apresenta sobre a contratação é a cota patronal da previdência social e aplicando as mudanças propostas nesta última reforma laboral, concretizam-se esses efeitos e também se conclui que a redução dos custos de demissão não acelera a decisão de contrata

    The subconvexity problem for \GL_{2}

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    Generalizing and unifying prior results, we solve the subconvexity problem for the LL-functions of \GL_{1} and \GL_{2} automorphic representations over a fixed number field, uniformly in all aspects. A novel feature of the present method is the softness of our arguments; this is largely due to a consistent use of canonically normalized period relations, such as those supplied by the work of Waldspurger and Ichino--Ikeda.Comment: Almost final version to appear in Publ. Math IHES. References updated

    Shared and Distinct Functions of the Transcription Factors IRF4 and IRF8 in Myeloid Cell Development

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    Interferon regulatory factor (IRF) 8 and IRF4 are structurally-related, hematopoietic cell-specific transcription factors that cooperatively regulate the differentiation of dendritic cells and B cells. Whilst in myeloid cells IRF8 is known to modulate growth and differentiation, the role of IRF4 is poorly understood. In this study, we show that IRF4 has activities similar to IRF8 in regulating myeloid cell development. The ectopic expression of IRF4 in myeloid progenitor cells in vitro inhibits cell growth, promotes macrophages, but hinders granulocytic cell differentiation. We also show that IRF4 binds to and activates transcription through the IRF-Ets composite sequence (IECS). Furthermore, we demonstrate that Irf8-/-Irf4-/- mice exhibit a more severe chronic myeloid leukemia (CML)-like disease than Irf8-/- mice, involving a disproportionate expansion of granulocytes at the expense of monocytes/macrophages. Irf4-/- mice, however, display no obvious abnormality in myeloid cell development, presumably because IRF4 is expressed at a much lower level than IRF8 in granulocyte-macrophage progenitors. Our results also suggest that IRF8 and IRF4 have not only common but also specific activities in myeloid cells. Since the expression of both the IRF8 and IRF4 genes is downregulated in CML patients, these results may add to our understanding of CML pathogenesis
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