4,837 research outputs found

    Magnetic Raman Scattering of Insulating Cuprates

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    We study the B1gB_{1g} and A1gA_{1g} Raman profiles of M2_{2}CuO4O_{4} (with M= La, Pr, Nd, Sm, Gd), Bi2_{2}Sr2_{2}Ca0.5_{0.5}Y0.5_{0.5}Cu2_{2}O8+y_{8+y}%, YBa2_{2}Cu3_{3}O6.2_{6.2} and PrBa2_{2}Cu2.7_{2.7}Al0.3_{0.3}O7_{7} insulating cuprates within the Loudon-Fleury theory, in the framework of an extended Hubbard model for moderate on-site Coulomb interaction UU. We calculate the non-resonant contribution to these Raman profiles by using exact diagonalization techniques and analyze two types of contributing mechanisms to the line shapes: 4-spin cyclic exchange and spin-phonon interactions. Although these interactions contribute to different parts of the spectra, together, they account for the enhanced linewidth and asymmetry of the B1gB_{1g} mode, as well as the non-negligible intensity of the A1gA_{1g} Raman line observed in these materials.Comment: 8 pages, 2 eps figures. To be published in PR

    Maxillary nerve block: A comparison between the greater palatine canal and high tuberosity approaches.

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    Aim: Analgesia and anxiolysis during dental procedures are important for dental care and patient compliance. This study aims to compare two classical maxillary nerve block (MNB) techniques: the greater palatine canal (GPC) and the high tuberosity (HT) approaches, seldom used in routine dental practice. Methods: The study was conducted on 30 patients, scheduled for sinus lift surgery, who were randomly divided into 2 groups: the GPC approach to the MNB was used in 15 and the HT one in the other 15 patients. Anxiolysis was also used, depending on the results of the pre- preoperative assessment. Patients\u2019 sensations/pain during the procedure, details about anesthesia, and the dentist\u2019s considerations were all recorded. Data are expressed as mean \ub1SD. Statistical tests including ANOVA, \u3c72 following Yates correction and linear regression analysis were carried out. A < 0.05 p value was considered significant. Results: Study results showed that the anesthesia was effective and constant in the molar and premolar area. Additional infiltrations of local anesthetics were necessary for vestibular and palatal areas in the anterior oral cavity, respectively, in the GPC and HT groups. The two techniques were equally difficult to carry out in the dentist\u2019s opinion. There were no differences in pain or unpleasant sensations between the two groups, nor were any anesthesia-related complications reported. Conclusion: The GPC approach ensures effective anesthesia in the posterior maxillary region as far as both the dental pulp and the palatal/vestibular mucous membranes are concerned; the HT approach did not guarantee adequate anesthesia of the pterygopalatine branch of the maxillary nerve. These regional anesthesia techniques were characterized by a low incidence of intra and postoperative pain, no noteworthy complications, and high patient satisfaction

    Imagens de satélite na escola: uma ferramenta para a percepção ambiental na construção do conhecimento.

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    A presente contribuição descreve a possibilidade de aprendizado dos conceitos da Geografia de paisagem e lugar usando imagens de satélite no ensino fundamental e introduz questões ambientais locais como forma de trabalhar a educação ambiental. São apresentados os requisitos metodológicos do sensoriamento remoto e da geografia relacionados aos processos de ensino aprendizagem. O objetivo do trabalho é inserir esses conceitos e mostrar a importância de alguns lugares no ambiente urbano de Campinas(SP), além de buscar despertar interesse dos professores diante de novas tecnologias a serem usadas na sala de aula. Como resultado, foi elaborado um livro paradidático e um jogo da memória. O material produzido auxiliou as crianças a compreenderem as questões ambientais locais e a desenvolverem uma visão das paisagens e lugares, usando as imagens de satélites de forma contextualizada e lúdica

    High intensity X/ γ photon beams for nuclear physics and photonics

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    In this manuscript we review the challenges of Compton back-scattering sources in advancing photon beam performances in the1−20MeVenergy range, underlining the design criteria bringing tomaximum spectral luminosity and briefly describing the main achieve-ments in conceiving and developing new devices (multi-bunch RF cav-ities and Laser recirculators) for the case of ELI-NP Gamma BeamSystem (ELI-NP-GBS)

    A muon source based on plasma accelerators

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    The conceptual design of a compact source of GeV-class muons is presented, based on a plasma based electron-gamma collider. Evaluations of muon flux, spectra and brilliance are presented, carried out with ad-hoc montecarlo simulations of the electron-gamma collisions. These are analyzed in the context of a large spread of the invariant mass in the e-gamma interaction, due to the typical characteristics of plasma self-injected GeV electron beams, carrying large bunch charges with huge energy spread. The availability of a compact point-like muon source, triggerable at nsec level, may open a completely new scenario in the muon radiography application field

    Electron beam transfer line design for plasma driven Free Electron Lasers

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    Plasma driven particle accelerators represent the future of compact accelerating machines and Free Electron Lasers are going to benefit from these new technologies. One of the main issue of this new approach to FEL machines is the design of the transfer line needed to match of the electron-beam with the magnetic undulators. Despite the reduction of the chromaticity of plasma beams is one of the main goals, the target of this line is to be effective even in cases of beams with a considerable value of chromaticity. The method here explained is based on the code GIOTTO [1] that works using a homemade genetic algorithm and that is capable of finding optimal matching line layouts directly using a full 3D tracking code.Comment: 9 Pages, 4 Figures. A related poster was presented at EAAC 201
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