3,638 research outputs found

    Segregation-induced grain boundary electrical potential in ionic oxide materials: A first principles model

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    A first principles continuum analytical model for cationic segregation to the grain boundaries in complex ceramic oxides is presented. The model permits one to determine the electric charge density and the segregation-induced electric potential profiles through the grain and can be extrapolated to the range of nanostructured grain sizes. The theoretical predictions are compared with existing data for yttria-stabilized tetragonal zirconia polycrystals. The implications for physical properties (mainly high temperature plasticity and hardening behaviour) are then discussed.Gobierno de España MAT2009-14351-C02-01, MAT2009-14351-C02-0

    Influence of ships emissions in the ultrafine particles pollution in an urban coastal air

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    Comunicación presentada en: V Reunión Española de Ciencia y Tecnología de Aerosoles – RECTA 2011 celebrada del 27 al 29 de junio de 2011 en CIEMAT, Madrid.Experimental data (2008-2009) of particle number (N≥2.5 nm diameter) and black carbon (BC) concen-trations and of gaseous pollutants recorded in the city of Santa Cruz de Tenerife was analyzed in order to asses the impact of ship emissions on the ultrafine particle (UFP) concentrations in coastal urban areas. The observed relationship between N and the other air pollutants, allowed segregating the contribu-tion of vehicle exhaust and of ship emissions to the UFP con-centrations in the urban ambient air. The influence of fresh vehicle exhaus

    Electric and magnetic dipolar response of Germanium spheres: Interference effects, scattering anisotropy and optical forces

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    We address the scattering cross sections, and their consequences, for submicrometer Germanium spheres. It is shown that there is a wide window in the near infrared where light scattering by these particles is fully described by their induced electric and magnetic dipoles. In this way, we observe remarkable anisotropic scattering angular distributions, as well as zero forward or backward scattered intensities, which until recently was theoretically demonstrated only for hypothetically postulated magnetodielectric spheres. Also, interesting new effects of the optical forces exerted on these objects are now obtained.Comment: 13 pages, 4 figure

    Indicadores de bienestar psicolĂłgico percibido en alumnos de EducaciĂłn FĂ­sica

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    Suplemento de artículos seleccionados con revisión del Congreso Andaluz de Psicología de la Actividad Física y el Deporte (13 : 2011 : Sevilla). Editores : José Carlos Caracuel ; Rocío Bohórquez.Adolescence is a critical step in learning healthy and wellness behaviours, which include physical activity; furthermore the habits developed during this phase may continue into adulthood. If psychological well-being is considered one of the factors that facilitates adhesion to exercise and health and allows physical exercise to be practiced, adequately perceiving indicators of well-being should be teachers' main objective in teaching physical education at school. We aimed to establish the correspondence between teaching styles in physical education teachers for organising classes and the indices of psychological well-being perceived by students in learning contexts. We conducted a correlational descriptive study between teaching styles indicators (n = 15) using the Styles Questionnaire Educational Profiles (PEE) (Magaz and Garcia, 1998) and the perceptions of subjective well-being by students (n = 150) between 12 and 16 years of age using the Spanish version of Ryff's Scale of Psychological Well-Being (Diaz et al., 2005), corresponding to compulsory secondary education. The data analysis suggests a positive correspondence between the indices of psychological well-being perceived by the students with the way in which their physical education teachers taught the subject. The results showed the importance of the pedagogical transmission of physical activity as a model that encourages adolescents' psychological well-being as a basis for healthy behaviours in adulthood

    Robust determination of the Higgs couplings: Power to the data

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    We study the indirect effects of new physics on the phenomenology of the recently discovered "Higgs-like" particle. In a model-independent framework these effects can be parametrized in terms of an effective Lagrangian at the electroweak scale. In a theory in which the S U ( 2 ) L Ă— U ( 1 ) Y gauge symmetry is linearly realized they appear at lowest order as dimension-six operators, containing all the standard model fields including the light scalar doublet, with unknown coefficients. We discuss the choice of operator basis which allows us to make better use of all the available data to determine the coefficients of the new operators. We illustrate our present knowledge of those by performing a global five-parameter fit to the existing data which allows simultaneous determination of the Higgs couplings to gluons, electroweak gauge bosons, bottom quarks, and tau leptons. We find that for all scenarios considered the standard model predictions for each individual Higgs coupling and observable are within the corresponding 90% C.L. allowed range, the only exception being the Higgs branching ratio into two photons for the scenario with standard couplings of the Higgs to fermions. We finish by commenting on the implications of the results for unitarity of processes at higher energies

    Constraining anomalous Higgs boson interactions

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    The recently announced Higgs boson discovery marks the dawn of the direct probing of the electroweak symmetry breaking sector. Sorting out the dynamics responsible for electroweak symmetry breaking now requires probing the Higgs boson interactions and searching for additional states connected to this sector. In this work, we analyze the constraints on Higgs boson couplings to the standard model gauge bosons using the available data from Tevatron and LHC. We work in a model-independent framework expressing the departure of the Higgs boson couplings to gauge bosons by dimension-six operators. This allows for independent modifications of its couplings to gluons, photons, and weak gauge bosons while still preserving the Standard Model (SM) gauge invariance. Our results indicate that best overall agreement with data is obtained if the cross section of Higgs boson production via gluon fusion is suppressed with respect to its SM value and the Higgs boson branching ratio into two photons is enhanced, while keeping the production and decays associated to couplings to weak gauge bosons close to their SM prediction

    Determining Triple Gauge Boson Couplings from Higgs Data

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    In the framework of effective Lagrangians with the S U ( 2 ) L Ă— U ( 1 ) Y symmetry linearly realized, modifications of the couplings of the Higgs field to the electroweak gauge bosons are related to anomalous triple gauge couplings (TGCs). Here, we show that the analysis of the latest Higgs boson production data at the LHC and Tevatron give rise to strong bounds on TGCs that are complementary to those from direct TGC analysis. We present the constraints on TGCs obtained by combining all available data on direct TGC studies and on Higgs production analysis

    Magneto-optical effects in interacting localized and propagating surface plasmon modes

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    We report that the effect of an external magnetic field on the propagation of surface plasmons can be effectively modified through the coupling between localized (LSP) and propagating (SPP) surface plasmons. When these plasmon modes do not interact, the main effect of the magnetic field is a modification of the wavevector of the SPP mode, leaving the LSP virtually unaffected. Once both modes start to interact, there is a strong variation of the magnetic field induced modification of the SPP dispersion curve and, simultaneously, the LSP mode becomes sensitive to the magnetic field.This work was supported by the EU (NMP3-SL- 2008-214107-Nanomagma), the Spanish MICINN (“MAGPLAS” MAT2008-06765-C02-01/NAN and “FUNCOAT” CONSOLIDER INGENIO 2010 CSD2008-00023), the Comunidad de Madrid (“NANOBIOMAGNET” S2009/MAT-1726 and “MICROSERES-CM” S2009/TIC-1476), and CSIC (“CRIMAFOT” PIF08-016-4). We thank A. Cebollada and J. M. García-Martín for growing and characterizing the Au/Co/Au trilayers and reading this manuscript, and R. Quidant and G.Badenes for fruitful discussions.Peer reviewe
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