2,769 research outputs found

    Lattice points in rational ellipsoids

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    AbstractWe combine exponential sums, character sums and Fourier coefficients of automorphic forms to improve the best known upper bound for the lattice error term associated to rational ellipsoids

    The LHC Dipole Geometry as Built in Industry

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    The LHC dipoles magnets are produced in 5 industrial production sites in Europe. The production is well underway and more than half of the total quantity has been delivered to CERN. One of the important characteristics of the dipole magnets is their geometry. To achieve the requested mechanical tolerances on the magnets, which are 15 m long and have a 28 t mass, the final assembly operations includes precise optical measurements. To ensure the good quality and high production rate, the final assembly procedure has been automated as much as possible. The authors report here about the assembly procedure, the features of the software that guides the optical measurements (and consequently the assembly operations) and the results obtained on the geometry in the different sites

    The Highly Oscillatory Behavior of Automorphic Distributions for SL(2)

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    Automorphic distributions for SL(2) arise as boundary values of modular forms and, in a more subtle manner, from Maass forms. In the case of modular forms of weight one or of Maass forms, the automorphic distributions have continuous first antiderivatives. We recall earlier results of one of us on the Holder continuity of these continuous functions and relate them to results of other authors; this involves a generalization of classical theorems on Fourier series by S. Bernstein and Hardy-Littlewood. We then show that the antiderivatives are non-differentiable at all irrational points, as well as all, or in certain cases, some rational points. We include graphs of several of these functions, which clearly display a high degree of oscillation. Our investigations are motivated in part by properties of "Riemann's nondifferentiable function", also known as "Weierstrass' function".Comment: 27 pages, 6 Figures; version 2 corrects misprints and updates reference

    First detection in Europe of the metallo-β-lactamase IMP-15 in clinical strains of Pseudomonas putida and Pseudomonas aeruginosa

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    AbstractIn a prospective study (2009–2011) in healthcare institutions from the Canary Islands (Spain), 6 out of 298 carbapenem non-susceptible Pseudomonas aeruginosa isolates produced a metallo-β-lactamase: four IMP-15, two VIM-2 (including one IMP-15-positive isolate) and one VIM-1. Multilocus sequence typing identified the single VIM-1-producing isolate as clone ST111 and two IMP-15-producing isolates as ST606, but, strikingly, bacterial re-identification revealed that the other three isolates (producing IMP-15 and/or VIM-2) were actually Pseudomonas putida. Further retrospective analysis revealed a very high prevalence (close to 50%) of carbapenem resistance in this environmental species. Hence, we report the simultaneous emergence in hospitals on the Canary Islands of P. putida and P. aeruginosa strains producing IMP-15, a metallo-β-lactamase not previously detected in Europe, and suggest an underestimated role of P. putida as a nosocomial reservoir of worrying transferable resistance determinants

    Estimación de la generación y composición de residuos sólidos en Papalotla, Tlaxcala

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    The objective of this work was to estimate the generation and composition of solid waste in the Colonies and Sections of Papalotla de Xicohténcat Municipality, Tlaxcala; in order to generate relevant information for the development of plans and management of solid waste in the study area. The samplings were carried out from April 22 to 29, 2019, in three randomly selected Colonies (El Potrero, Xilotzinco and San Buenaventura). The generation estimation was carried out using the procedure described in NMX-AA-61, with modifications in the sampling, since garbage collection trucks from the Municipal Services area were used. The characterization was carried out in accordance with NMX-AA-15-1985, which establishes the quartering method for municipal solid waste. With the average values of per capita generation, the generation for the rest of the colonies was estimated for different periods of time, in the same way we proceeded with the solid waste composition data. The results showed that Papalotla, Tlaxcala generates 44.3 tons of waste daily, of which 41% are organic materials, 20% plastic, 14% infectious biological material, 12% cardboard and paper, 7.5% glass, and the rest metals.El objetivo de este trabajo fue estimar la generación y composición de residuos sólidos de las Colonias y Secciones del Municipio de Papalotla de Xicohténcatl, Tlaxcala; con la finalidad de generar información pertinente para la elaboración de planes y manejo de residuos sólidos en la zona de estudio. Los muestreos se realizaron del 22 al 29 de abril del 2019, en tres Colonias seleccionadas al azar (El Potrero, Xilotzinco y San Buenaventura). La estimación de la generación se realizó empleando el procedimiento descrito en la NMX-AA-61, con modificaciones en el muestreo, ya que se utilizaron los camiones recolectores de basura del área de Servicios Municipales. La caracterización se realizó de acuerdo con la NMX-AA-15-1985, que establece el método de cuarteo para residuos sólidos municipales. Con los valores promedio de la generación per cápita, se estimó la generación para el resto de las colonias para diferentes periodos de tiempo, de igual forma se procedió con los datos de composición de residuos sólidos. Los resultados mostraron que Papalotla, Tlaxcala se generan diariamente 44.3 toneladas de residuos, de los cuales 41% son materiales orgánicos, 20% plásticos, 14 % material biológico infeccioso, 12% cartón y papel, 7.5% vidrio y el resto metales

    Novel design of a parallax free Compton enhanced PET scanner

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    Molecular imaging by PET is a powerful tool in modern clinical practice for cancer diagnosis. Nevertheless, improvements are needed with respect to the spatial resolution and sensitivity of the technique for its application to specific human organs (breast, prostate, brain, etc.), and to small animals. Presently, commercial PET scanners do not detect the depth of interaction of photons in scintillators, which results in a not negligible parallax error. We describe here a novel concept of PET scanner design that provides full three-dimensional (3D) gamma reconstruction with high spatial resolution over the total detector volume, free of parallax errors. It uses matrices of long scintillators read at both ends by hybrid photon detectors. This so-called 3D axial concept also enhances the gamma detection efficiency since it allows one to reconstruct a significant fraction of Compton scattered events. In this note, we describe the concept, a possible design and the expected performance of this new PET device. We also report about first characterization measurements of 10 cm long YAP:Ce scintillation crystals. r 2004 Elsevier B.V. All rights reserved

    IAOx induces the SUR phenotype and differential signalling from IAA under different types of nitrogen nutrition in Medicago truncatula roots

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    Indole-3-acetaldoxime (IAOx) is a particularly relevant molecule as an intermediate in the pathway for tryptophan-dependent auxin biosynthesis. The role of IAOx in growth-signalling and root phenotype is poorly studied in cruciferous plants and mostly unknown in non-cruciferous plants. We synthesized IAOx and applied it to M. truncatula plants grown axenically with NO3 -, NH4 + or urea as the sole nitrogen source. During 14 days of growth, we demonstrated that IAOx induced an increase in the number of lateral roots, especially under NH4 + nutrition, while elongation of the main root was inhibited. This phenotype is similar to the phenotype known as superroot previously described in SUR1- and SUR2-defective Arabidopsis mutants. The effect of IAOx, IAA or the combination of both on the root phenotype was different and dependent on the type of N-nutrition. Our results also showed the endogenous importance of IAOx in a legume plant in relation to IAA metabolism, and suggested IAOx long-distance transport depending on the nitrogen source provided. Finally, our results point out to CYP71A as the major responsible enzymes for IAA synthesis from IAOx, while they exclude indole-3-acetaldehyde oxidases. © 2019 Elsevier B.V.This work was supported by the grants AGL2017-86293-P and CGL2017-84723-P from the Spanish Ministry of Economy and Competitiveness (MINECO) , AGL2014-52396-P from the Ministry of Science Innovation and Universities (MICINN) , and IT932-16 from the Basque Government, Spain . JB and PL-G are holders of PhD fellowships from the Public University of Navarre. ACh received a Juan de la Cierva initiation grant FJCI-2016-27905 and RE received a Juan de la Cierva incorporation grant IJCI-2014-21452. This research was also supported by the Basque Government through the BERC 2018-2021 program, and by the Spanish Ministry of Science, Innovation and Universities through the BC3 María de Maeztu excellence accreditation (MDM-2017-0714)

    Novel geometrical concept of a high-performance brain PET scanner. Principle, design and performance estimates

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    We present the principle, a possible implementation and performance estimates of a novel geometrical concept for a high-resolution positron emission tomograph. The concept, which can be for example implemented in a brain PET device, promises to lead to an essentially parallax-free 3D image reconstruction with excellent spatial resolution and constrast, uniform over the complete field of view. The key components are matrices of long axially oriented scintillator crystals which are read out at both extremities by segmented Hybrid Photon Detectors. We discuss the relevant design considerations for a 3D axial PET camera module, motivate parameter and material choices, and estimate its performance in terms of spatial and energy resolution. We support these estimates by Monte Carlo simulations and in some cases by first experimental results. From the performance of a camera module, we extrapolate to the reconstruction resolution of a 3D axial PET scanner in a semi-analytical way and compare it to an existing state-of-the art brain PET device. We finally describe a dedicated data acquisition system, capable to fully exploit the advantages of the proposed concept. We conclude that the proposed 3D axial concept and the discussed implementation is a competitive approach for high-resolution brain PET. Excellent energy resolution and Compton enhanced sensitivity are expected to lead to high-quality reconstruction and reduced scanning times

    Study of Z Boson Pair Production in e+e- Collisions at LEP at \sqrt{s}=189 GeV

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    The pair production of Z bosons is studied using the data collected by the L3 detector at LEP in 1998 in e+e- collisions at a centre-of-mass energy of 189 GeV. All the visible final states are considered and the cross section of this process is measured to be 0.74 +0.15 -0.14 (stat.) +/- 0.04 (syst.) pb. Final states containing b quarks are enhanced by a dedicated selection and their production cross section is found to be 0.18 +0.09 -0.07 (stat.) +/- 0.02 (syst.) pb. Both results are in agreement with the Standard Model predictions. Limits on anomalous couplings between neutral gauge bosons are derived from these measurements
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