6,188 research outputs found

    Phenomenology of an extended IDM with loop-generated fermion mass hierarchies

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    We perform a comprehensive analysis of the most distinctive and important phenomenological implications of the recently proposed mechanism of sequential loop generation of strong hierarchies in the Standard Model (SM) fermion mass spectra. This mechanism is consistently realized at the level of renormalizable interactions in an extended variant of the Inert Higgs Doublet model, possessing the additional Z2(1)×Z2(2)Z_{2}^{(1)}\times Z_{2}^{(2)} discrete and U1XU_{1X} gauge family symmetries, while the matter sectors of the SM are extended by means of SU2LSU_{2L}-singlet scalars, heavy vector-like leptons and quarks, as well as right-handed neutrinos. We thoroughly analyze the most stringent constraints on the model parameter space, coming from the ZZ^{\prime } collider searches, related to the anomaly in lepton universality, and the muon anomalous magnetic moment, as well as provide benchmark points for further tests of the model and discuss possible "standard candle" signatures relevant for future explorations.Comment: Version accepted for publication in EPJC. arXiv admin note: text overlap with arXiv:1901.0276

    Structural and optical properties of compensated microcrystalline silicon films

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    Boron-doped microcrystalline silicon films were deposited in a plasma enhanced chemical vapor deposition (PECVD) system using silane (SiH4) diluted in hydrogen, and diborane (B2H6) as a dopant gas. The effects of the Boron concentration on the optical and structural properties were investigated by the constant-photocurrent method (CPM) and atomic force microscopy (AFM) measurements. The variations in the optical constants (refractive index, absorption coefficient and optical gap) as a function of wavelength were carried out from the optical transmission and CPM spectra. By increasing the doping level, a systematic increase in the absorption coefficient spectra in the low-energy region between 0.7 - 1.2 eV was observed. It was found that the increase of Boron concentration in the samples results in changes of the grain size. Correlations between optical properties and the density of states (DOS) were also studied.Fil: Dussan, A.. Universidad Nacional de Colombia; ColombiaFil: Koropecki, Roberto Roman. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Arce, Roberto Delio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Schmidt, Javier Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentin

    Planning the smart city

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    Explaining variation in parents' and their children's stress during COVID-19 lockdowns

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    The coronavirus pandemic poses a substantial threat to people across the globe. In the first half of 2020, governments limited the spread of virus by imposing diverse regulations. These regulations had a particular impact on families as parents had to manage their occupational situation and childcare in parallel. Here, we examine a variation in parents' and children's stress during the lockdowns in the first half of 2020 and detect the correlates of families' stress. Between April and June 2020, we conducted an explorative online survey among n = 422 parents of 3- to 10-year-old children residing in 17 countries. Most participants came from Germany (n = 274), Iran (n = 70), UK (n = 23), and USA (n = 23). Parents estimated their own stress, the stress of their own children, and various information on potential correlates (e.g., accommodation, family constellation, education, community size, playtime for children, contact with peers, media consumption, and physical activity). Parents also stated personal values regarding openness to change, self-transcendence, self-enhancement, and conservation. The results indicate a substantial variation in the stress levels of families and their diverse reactions to regulations. Media consumption by children commonly increased in comparison to the time before the pandemic. Parents raising both pre-school- and school-aged children were at a particular risk of experiencing stress in response to regulations. Estimated stress and reactions varied with the age of children and the personal values of parents, suggesting that such variables need to be considered when implementing and evaluating regulations and supporting young families in the current and future pandemi

    Density of States in Thin Boron-Doped Microcrystalline Silicon Films Estimated from the Thermally Stimulated Conductivity Method

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    In this work, a series of boron-doped microcrystalline silicon samples [μc-Si:H(B)] were deposited by plasma-enhanced chemical vapor deposition, using silane (SiH4) diluted in hydrogen, and diborane (B2H6) as a dopant gas. The concentration of B2H6 in SiH4 was varied in the range of 0-100 ppm. The density of states was obtained from the thermally stimulated conductivity technique and compared with results obtained by the modulated photoconductivity methods. To explain the poor agreement between the density of states obtained from the thermally stimulated conductivity and the other methods, it is shown by means of numerical simulations that the density of states is very sensitive to experimental errors introduced in the calculation of the μn τn product (mobility of electron × lifetime of the electron). The thermally stimulated conductivity method is applied here for the first time to calculate the density of defect states in the forbidden band of μc-Si:H samples.Fil: Dussan, A.. Universidad Nacional de Colombia. Departamento de Física; ColombiaFil: Schmidt, Javier Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Física del Litoral; ArgentinaFil: Koropecki, Roberto Roman. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Física del Litoral; Argentin

    3D fluorescence microscopy with isotropic resolution on the nanoscale

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    The resolution of any linear imaging system is given by its point-spread-function (PSF) quantifying the blur of an object point in the image. The sharper the PSF, the better is the resolution. In standard fluorescence microscopy, however, diffraction dictates a PSF with a cigar-shaped main maximum, called the focal spot which extends over at least half the wavelength of light (L = 400-800 nm) in the focal plane and > L along the optic axis (z). While concepts have evolved to sharpen the focal spot both laterally and axially, none of them has reached their ultimate goal: a spherical spot that can be arbitrarily downscaled in size. Herein, I introduce such a fluorescence microscope and demonstrate the creation of spherical focal spots of 40-45 nm (~ L/16) diameter that is pushed down to 21-30 nm (~ L/30) under suitable conditions. Fully relying on focused light, this lens-based fluorescence nanoscope unravels the interior of cells noninvasively, uniquely dissecting their sub-L sized organelles. Further fields of application open up, such as the characterization of novel nanomaterials

    Gridella: an open and efficient Gnutella-compatible Peer-to-Peer System based on the P-Grid approach

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    This thesis describes the Peer-to-Peer Application Gridella. The decentralized architecture of P2P systems enables each peer to fulfill search requests solely by local interactions. The system described in this thesis scales to high numbers of peers and data items and remains available in spite of failing peers. Further, probabilities for successful search requests can be given. Gridella is based on the P-Grid approach~\cite{infosysdb:Aberer01a, infosysdb:Aberer02c} and is designed to be compatible with Gnutella `` infiltrate'' the existing Gnutella infrastructure and enable an simple migration. P-Grid increases the efficiency of search requests, and reduces the required bandwidth for system maintenance. On the basis of an analysis of the existing Gnutella infrastructure and its problems I describe the foundations of P-Grid. The developed application supports the existing Gnutella and the new Gridella protocol. Then the architecture and the communication between the systems are described in detail

    Obtención de Películas Delgadas de Silicio Policristalino a partir de Clorosilanos en Reactores de CVD

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    En este trabajo se presentan resultados obtenidos en la deposición y caracterización estructural de láminas delgadas de silicio policristalino. Como método de deposición se usó el CVD térmico a partir de triclorosilano, y como sustrato un vidrio comercial de alta temperatura. Se logró la deposición de películas policristalinas, con tamaños de grano entre 0,2 y 0,5 micrones, a temperaturas de entre 730 y 840 ºC. Las muestras presentan un crecimiento tipo columnar y una clara orientación cristalina (2 2 0). Estas características serían propicias para el transporte electrónico en la dirección perpendicular al sustrato.In this work, results obtained from the deposition and structural characterization of polycrystalline silicon thin films are presented. Thermal CVD from trichlorosilane was used as deposition method, and a high temperature commercial glass was used as substrate. The deposition of polycrystalline films with grain sizes between 0.2 and 0.5 microns was achieved, at temperatures in the range of 730 to 840 ºC. The samples present a columnar type growth and a clear (2 2 0) crystal orientation. This characteristics would be suitable for the electronic transport in the direction perpendicular to the substrate.Fil: Benvenuto, Ariel Gastón. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); ArgentinaFil: Schmidt, Javier Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); ArgentinaFil: Buitrago, Roman Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); Argentin
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