Upconversion of a relativistic Coulomb field terahertz pulse to the near infrared

We demonstrate the spectral upconversion of a unipolar subpicosecond terahertz (THz) pulse, where the THz pulse is the Coulomb field of a single relativistic electron bunch. The upconversion to the optical allows remotely located detection of long wavelength and nonpropagating components of the THz spectrum, as required for ultrafast electron bunch diagnostics. The upconversion of quasimonochromatic THz radiation has also been demonstrated, allowing the observation of distinct sum- and difference-frequency mixing components in the spectrum. Polarization dependence of first and second order sidebands at ωopt±ωTHz, and ωopt±2ωTHz, respectively, confirms the χ(2) frequency mixing mechanism

Longtitudinal electron beam diagnostics via upconversion of THz to visible radiation

Longitudinal electro-optic electron bunch diagnostics has been successfully applied at several accelerators. The electro-optic effect can be seen as an upconversion of the Coulomb field of the relativistic electron bunch (THz radiation) to the visible spectral range, where a variety of standard diagnostic tools are available. Standard techniques to characterise femtosecond optical laser pulses (auto- and cross-correlators) have led to the schemes that can measure electron bunch profiles with femtosecond resolution. These techniques require, however, well synchronized femtosecond laser pulses, in order to obtain the desired temporal resolution. Currently, we are exploring other electro-optic variants which require less advanced laser systems and will be more amenable to beam based longitudinal feedback applications. The first results of one such new scheme will be presented in this paper

Laboratory IR Spectra of the Ionic Oxidized Fullerenes C₆₀O⁺and C₆₀OH⁺

[Image: see text] We present the first experimental vibrational spectra of gaseous oxidized derivatives of C(60) in protonated and radical cation forms, obtained through infrared multiple-photon dissociation spectroscopy using the FELIX free-electron laser. Neutral C(60)O has two nearly iso-energetic isomers: the epoxide isomer in which the O atom bridges a CC bond that connects two six-membered rings and the annulene isomer in which the O atom inserts into a CC bond connecting a five- and a six-membered ring. To determine the isomer formed for C(60)O(+) in our experiment—a question that cannot be confidently answered on the basis of the DFT-computed stabilities alone—we compare our experimental IR spectra to vibrational spectra predicted by DFT calculations. We conclude that the annulene-like isomer is formed in our experiment. For C(60)OH(+), a strong OH stretch vibration observed in the 3 μm range of the spectrum immediately reveals its structure as C(60) with a hydroxyl group attached, which is further confirmed by the spectrum in the 400–1600 cm(–1) range. We compare the experimental spectra of C(60)O(+) and C(60)OH(+) to the astronomical IR emission spectrum of a fullerene-rich planetary nebula and discuss their astrophysical relevance

The aromatic nature of residue 66 of the 11-kDa subunit of ubiquinol-cytochrome <i>c</i> oxidoreductase of the yeast <i>Saccharomyces cerevisiae</i> is important for the assembly of a functional enzyme

AbstractTransformation of multi- and single-copy plasmids carrying a mutated version (LTN2, region 66-YWYWW-70 replaced by SASAA) of QCR8, the gene encoding the 11-kDa subunit of ubiquinol-cytochrome c oxidoreductase of Saccharomyces cerevisiae, to a QCR80 strain indicated the importance of this aromatic region for the assembly of a functional enzyme. Sequencing of plasmids giving spontaneous restoration of growth to some colonies among the single-copy LTN2 transformants showed that changing the sequence SASAA into the sequence FASAA could, to a large extent, overcome the observed assembly defect, indicating the importance of the aromatic nature of residue 66

Plurilingüismo: por qué ser personas plurilingües y cuándo iniciar el aprendizaje

Treball Final de Grau en Mestre o Mestra d'Educació Primària. Codi: MP1040. Curs acadèmic: 2016/2017Entendemos como plurilingüismo aquellas variedades lingüísticas que utiliza un mismo locutor, ya sea la lengua materna y todas aquellas adquiridas posteriormente. Tenemos al alcance la opción de enriquecernos con lenguas diferentes a la nuestra y esto se considera un aspecto muy importante para el acceso a las manifestaciones culturales. La lengua regula nuestro pensamiento y todas nuestras ideas apoyadas por bases lingüísticas. Además, como seres sociales contamos con la necesidad de relacionarnos y de comunicarnos, para hacernos hueco en el progreso continuo de la sociedad. Por esta misma razón, se deben tener en cuenta ciertos aspectos culturales, características personales de los individuos de una sociedad y a qué estratificación social pertenecen, para poder llevar a cabo una Competencia Comunicativa adecuada. La conciencia es cada vez mayor en cuanto a la función que desempeñan los idiomas en el desarrollo, la diversidad cultural y en el fortalecimiento de la cooperación y la conservación del patrimonio cultural. Siempre se ha considerado esencial el aprendizaje de idiomas desde edades tempranas para poder exprimir esos conocimientos de cara al futuro, pero, ¿qué impacto tiene el plurilingüismo y el aprendizaje de nuevas lenguas en edades adultas? El derecho a aprender a lo largo de toda la vida es cada vez más ratificado, no obstante, la educación de adultos se encuentra muy rezagada con respecto a los demás sectores de la enseñanza. A lo largo de este trabajo de investigación descubriremos las ventajas cognitivas que presenta el plurilingüismo en la Educación para Adultos así como la eficiencia y los beneficios a los cuales llevan