531 research outputs found

    Colour Octet effects in Quarkonium Physics

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    The importance of including colour octet contributions in describing decay and production of quarkonium states is briefly discussed for two cases : the radiative decays of the Υ\Upsilon and the production of J/ψJ/\psi in the inclusive BB decays. It is shown how information on the non-perturbative matrix elements can be obtained by comparing the theoretical expressions computed at next-to-leading order in αs\alpha_s with the experimental data.Comment: 4 pages, Latex (espcrc2.sty), 1 figure. Talk presented at QCD'98, Montpellier, July 2-8, 1998; to appear in Nucl. Phys. B (Proc. Suppl.

    Surface and sub-surface oxidation of thin films using Low Energy Ion Scattering

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    Ru and ZrN are candidate capping layers for applications such as catalysis, electronics and optical coatings: Ru exhibits a low resistivity, high thermal stability, excellent oxidation resistance and good diffusion capabilities. ZrN is thermally stable, and is known for its good mechanical properties. Although the oxidation process has been studied for both materials, the surface and especially the sub-surface oxidation is not properly understood and well addressed. We use the sub-monolayer surface sensitivity of the low energy ion scattering (LEIS) technique for in-situ monitoring of surface oxidation and determination of the oxygen sticking probabilities. From the LEIS in-depth signal, sub-nanometer sub-surface oxidation can be determined as a function of time and from these data oxygen diffusion constants can be extracted. These data support the applications for which adequate protecting surface films are required. i) Author to whom correspondence should be addressed. Electronic mail: [email protected]

    Serological autoimmune profile of systemic lupus erythematosus in deep and non-deep endometriosis patients

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    Several studies have reported a high prevalence of autoimmune diseases such as systemic lupus erythematosus (SLE) in endometriosis patients. The aim of this study was to evaluate the SLE autoimmune antibody profile in patients with deep (DE) and non-deep endometriosis (Non-DE).Four groups of premenopausal patients were evaluated: patients with DE (n = 50); patients with ovarian endometriomas (Non-DE; n = 50); healthy patients without endometriosis (C group; n = 45); and SLE patients without endometriosis (SLE group; N = 46). Blood samples were obtained and the standard SLE autoimmune profile was evaluated in all patients. Pain symptoms related to endometriosis and clinical SLE manifestations were also recorded.The DE group presented a statistically significant higher proportion of patients with antinuclear antibodies (ANA) (20%) compared to the Non-DE group (4%) and C group (2.2%). Levels of complement were more frequently lower among DE and Non-DE patients although differences did not reach statistical significance. Similarly, anti-dsDNA antibodies and anticoagulant lupus were positive in more patients of the DE group but did not reach statistical significance. The DE group complained of more arthralgia and asthenia compared to the Non-DE and C groups.The results of this study showed higher positivity of ANA and greater arthralgia and asthenia in patients with DE compared with Non-DE patients and healthy controls, suggesting that they may have a higher susceptibility to autoimmune diseases and present more generalized pain.Copyright © 2023. Published by Elsevier B.V

    Surface and sub-surface thermal oxidation of thin ruthenium films

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    A mixed 2D (film) and 3D (nano-column) growth of ruthenium oxide has been experimentally observed for thermally oxidized polycrystalline ruthenium thin films. Furthermore, in situ x-ray reflectivity upon annealing allowed the detection of 2D film growth as two separate layers consisting of low density and high density oxides. Nano-columns grow at the surface of the low density oxide layer, with the growth rate being limited by diffusion of ruthenium through the formed oxide film. Simultaneously, with the growth of the columns, sub-surface high density oxide continues to grow limited by diffusion of oxygen or ruthenium through the oxide fil

    D-wave heavy quarkonium production in fixed target experiments

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    We calculate the DD-wave heavy quarkonium production at fixed target experiments under the NRQCD factorization formalism. We find that the color octet contributions are two orders of magnitude larger than color-singlet contributions if color-octet matrix elements are taken according to the NRQCD velocity scaling rules. Within the theoretical uncertainties, the prediction for the production rate of 22^{--} DD-wave charmonium state agrees with the preliminary result of E705 and other experiments. Searching for the 11^{--} DD-wave state ψ(3770)\psi(3770) is further suggested.Comment: 13pages, 4 PS figures, final vertion to appear in PR

    From Construction Workers to Architects: Developing Scientific Research Capacity in Low-Income Countries

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    Solving global health challenges in a sustainable manner depends on explicitly addressing scientific capacity-building needs, as well as establishing long-term, meaningful partnerships with colleagues in the developing world

    Estimación de los costes de construcción de viviendas rústicas mediante Redes Neuronales Artificiales

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    The Public Administration and the private developer seek to have a prior knowledge of the costs of any building. There are numerous methodologies in the literature that allow the real estate valuation of a property, but it has always been done for urban houses in large or medium-sized cities. This research proposes the use of Artificial Intelligence for the study of rustic houses in small cities such as Caceres (Spain). The research proposes a procedure of Artificial Neural Networks (ANN) to achieve on the one hand, to estimate, through an automatic method, the construction cost of rustic houses and, on the other hand, to identify the most determining attributes in its final price and its marginal weight. The designed ANN establishes as more influential variables in the final price of the property the wet spaces (bathrooms and kitchen), the constructed surface and the age in this order, differentiating themselves from the most determining variables in the price of urban houses in large or medium-sized cities that are the constructed surface and its location.La Administración Pública y el promotor privado buscan tener un conocimiento previo de los costes de cualquier edificación. Existen en la literatura numerosas metodologías que permiten realizar la valoración de un inmueble, pero siempre se ha realizado para viviendas urbanas en ciudades grandes o medianas. Esta investigación propone el uso de Inteligencia Artificial para el estudio de viviendas rústicas en pequeñas ciudades como la de Cáceres (España). La investigación propone un procedimiento de Redes Neuronales Artificiales (RNA) para conseguir por un lado estimar a través de un método automático el coste de construcción de la vivienda rústica y por otro, identificar los atributos más determinantes en su precio final. La RNA diseñada establece como variables más influyentes en el precio final del inmueble los espacios húmedos (baños y cocina), la superficie construida y la antigüedad por este orden, diferenciándose de las variables más determinantes en el precio de las viviendas urbanas en grandes o medianas ciudades que son la superficie construida y su ubicación

    Comet Machholz (C/2004 Q2): morphological structures in the inner coma and rotation parameters

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    Extensive observations of comet C/2004 Q2 (Machholz) were carried out between August 2004 and May 2005. The images obtained were used to investigate the comet's inner coma features at resolutions between 350 and 1500 km/pixel. A photometric analysis of the dust outflowing from the comet's nucleus and the study of the motion of the morphological structures in the inner coma indicated that the rotation period of the nucleus was most likely around 0.74 days. A thorough investigation of the inner coma morphology allowed us to observe two main active sources on the comet's nucleus, at a latitude of +85{\deg} \pm 5{\deg} and +45{\deg} \pm 5{\deg}, respectively. Further sources have been observed, but their activity ran out quite rapidly over time; the most relevant was at latcom. = 25{\deg} \pm 5{\deg}. Graphic simulations of the geometrical conditions of observation of the inner coma were compared with the images and used to determine a pole orientation at RA=95{\deg} \pm 5{\deg}, Dec=+35{\deg} \pm 5{\deg}. The comet's spin axis was lying nearly on the plane of the sky during the first decade of December 2004.Comment: 29 pages, 8 figures, 3 table

    Optimized Two-Baseline Beta-Beam Experiment

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    We propose a realistic Beta-Beam experiment with four source ions and two baselines for the best possible sensitivity to theta_{13}, CP violation and mass hierarchy. Neutrinos from 18Ne and 6He with Lorentz boost gamma=350 are detected in a 500 kton water Cerenkov detector at a distance L=650 km (first oscillation peak) from the source. Neutrinos from 8B and 8Li are detected in a 50 kton magnetized iron detector at a distance L=7000 km (magic baseline) from the source. Since the decay ring requires a tilt angle of 34.5 degrees to send the beam to the magic baseline, the far end of the ring has a maximum depth of d=2132 m for magnetic field strength of 8.3 T, if one demands that the fraction of ions that decay along the straight sections of the racetrack geometry decay ring (called livetime) is 0.3. We alleviate this problem by proposing to trade reduction of the livetime of the decay ring with the increase in the boost factor of the ions, such that the number of events at the detector remains almost the same. This allows to substantially reduce the maximum depth of the decay ring at the far end, without significantly compromising the sensitivity of the experiment to the oscillation parameters. We take 8B and 8Li with gamma=390 and 656 respectively, as these are the largest possible boost factors possible with the envisaged upgrades of the SPS at CERN. This allows us to reduce d of the decay ring by a factor of 1.7 for 8.3 T magnetic field. Increase of magnetic field to 15 T would further reduce d to 738 m only. We study the sensitivity reach of this two baseline two storage ring Beta-Beam experiment, and compare it with the corresponding reach of the other proposed facilities.Comment: 17 pages, 3 eps figures. Minor changes, matches version accepted in JHE
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