670 research outputs found

    Sobre organització industrial: Endegament de la producció d'un taller

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    Metal·lografia i raigs X

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    Els moderns materials magnètics

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    Open charm meson in nuclear matter at finite temperature beyond the zero range approximation

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    The properties of open charm mesons, DD, Dˉ\bar D, DsD_s and Dˉs\bar D_s in nuclear matter at finite temperature are studied within a self-consistent coupled-channel approach. The interaction of the low lying pseudoscalar mesons with the ground state baryons in the charm sector is derived from a tt-channel vector-exchange model. The in-medium scattering amplitudes are obtained by solving the Lippmann-Schwinger equation at finite temperature including Pauli blocking effects, as well as DD, Dˉ\bar D, DsD_s and Dˉs\bar D_s self-energies taking their mutual influence into account. We find that the in-medium properties of the DD meson are affected by the DsD_s-meson self-energy through the intermediate DsYD_s Y loops coupled to DNDN states. Similarly, dressing the Dˉ\bar{D} meson in the DˉY\bar{D}Y loops has an influence over the properties of the Dˉs\bar{D}_s meson.Comment: 23 pages, 9 figures, 2 table

    Dynamically generated open charmed baryons beyond the zero range approximation

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    The interaction of the low lying pseudo-scalar mesons with the ground state baryons in the charm sector is studied within a coupled channel approach using a t-channel vector-exchange driving force. The amplitudes describing the scattering of the pseudo-scalar mesons off the ground-state baryons are obtained by solving the Lippmann--Schwinger equation. We analyze in detail the effects of going beyond the t=0t=0 approximation. Our model predicts the dynamical generation of several open charmed baryon resonances in different isospin and strangeness channels, some of which can be clearly identified with recently observed states.Comment: 7 figures, 8 table

    Charmed nuclei within a microscopic many-body approach

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    Single-particle energies of the Λc\Lambda_c chamed baryon are obtained in several nuclei from the relevant self-energy constructed within the framework of a perturbative many-body approach. Results are presented for a charmed baryon-nucleon (YcNY_cN) potential based on a SU(4) extension of the meson-exchange hyperon-nucleon potential A~\tilde A of the J\"{u}lich group. Three different models (A, B and C) of this interaction, that differ only on the values of the couplings of the scalar σ\sigma meson with the charmed baryons, are considered. Phase shifts, scattering lengths and effective ranges are computed for the three models and compared with those predicted by the YcNY_cN interaction derived in Eur. Phys. A {\bf 54}, 199 (2018) from the extrapolation to the physical pion mass of recent results of the HAL QCD Collaboration. Qualitative agreement is found for two of the models (B and C) considered. Our results for Λc\Lambda_c-nuclei are compatible with those obtained by other authors based on different models and methods. We find a small spin-orbit splitting of the p,dp-, d- and ff-wave states as in the case of single Λ\Lambda-hypernuclei. The level spacing of Λc\Lambda_c single-particle energies is found to be smaller than that of the corresponding one for hypernuclei. The role of the Coulomb potential and the effect of the coupling of the ΛcN\Lambda_cN and ΣcN\Sigma_cN channels on the single-particle properties of Λc\Lambda_c-nuclei are also analyzed. Our results show that, despite the Coulomb repulsion between the Λc\Lambda_c and the protons, even the less attractive one of our YcNY_cN models (model C) is able to bind the Λc\Lambda_c in all the nuclei considered. The effect of the ΛcNΣcN\Lambda_cN-\Sigma_cN coupling is found to be almost negligible due to the large mass difference of the Λc\Lambda_c and Σc\Sigma_c baryons.Comment: 10 pages, 6 figures, 4 table

    Generalized transverse resonance analysis of planar discontinuities considering the edge effect

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    Mode-matching related techniques such as the Generalized Transverse Resonance Method (GTR) suffer from the relative convergence phenomenon. To reduce its influence, we present a technique consisting of the application of basis functions incorporating the singular behavior of fields at edges and an optimal modal ratio. We present the results obtained analyzing a uniform finline and a short-circuited finline which demonstrate the minimization of the relative convergence phenomenon, allowing a fast and accurate analysis on a low-cost personal computer.Peer Reviewe

    La coxartrosis en los pacientes con osteopetrosis: su tratamiento quirúrgico

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    Se presentan un caso de osteopetrosis en un paciente de 22 años de edad que consultó por dolor en la cadera izquierda, siendo diagnosticado de coxartrosis izquierda secundaria a la osteopetrosis. Fue tratado inicialmente de forma quirúrgica realizándosele una osteotomía de la cadera afectada. Varios años después, tras la reaparición del dolor se procedió a la implantación de una prótesis total de cadera que evolucionó satisfactoriamente.A case of osteopetrosis in a 22-year-old patient who consulted by pain in the left hip is presented. He was diagnosed of degenerative osteoarthritis of the left hip secondary to osteopetrosis. Initially, it was treated surgically by an osteotomy of the proximal femur. Several years later\ after the pain reappearance, the authors treated the patient by a total hip arthroplasty with satisfactory outcome

    Atmospheric dispersion of airborne pollen evidenced by near-surface and columnar measurements in Barcelona, Spain

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    Hourly measurements of pollen near-surface concentration and lidar-derived profiles of particle backscatter coefficients and of volume and particle depolarization ratios during a 5-day pollination event observed in Barcelona, Spain, between 27 – 31 March, 2015, are presented. Maximum hourly pollen concentrations of 4700 and 1200 m-3 h-1 were found for Platanus and Pinus, respectively, which represented together more than 80 % of the total pollen. Everyday a clear diurnal cycle caused by the vertical transport of the airborne pollen was visible on the lidar-derived profiles of the backscatter coefficient with maxima usually reached between 12 and 15 UT. A method based on the lidar polarization capabilities was used to retrieve the contribution of the pollen to the total signal. On average the diurnal (9 – 17 UT) pollen aerosol optical depth (AOD) was 0.05 which represented 29 % of the total AOD, the volume and particle depolarization ratios in the pollen plume were 0.08 and 0.14, respectively, and the diurnal mean of the height of the pollen plume was found at 1.24 km. The dispersion of the Platanus and Pinus in the atmosphere was simulated with the Nonhydrostatic Multiscale Meteorological Model on the B grid at the Barcelona Supercomputing Center with a newly developed Chemical Transport Model (NMMB/BSC-CTM). Model near-surface daily concentrations were compared to our observations at two sites: in Barcelona and Bellaterra (12 km NE of Barcelona). Model hourly concentrations were compared to our observations in Barcelona.Peer ReviewedPostprint (author's final draft
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