721 research outputs found

    Characterization of the hospitalization of children and adolescents with cancer

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    This study characterizes hospitalizations of children and adolescents with cancer, from 1998 to 2008, to describe the clientele in follow-up in the Regional Health Area of Ribeirão Preto, SP, Brazil. Morbidity was surveyed in Ribeirão Preto, SP, Brazil, using hospitalization data from the Unified Health System. The studied variables included: origin, residence, year when care was provided, deaths, age and gender of patients diagnosed with child and adolescent cancer according to the International Classification of Disease 10th edition, Chapter II. The results indicated 7,234 hospitalizations of individuals younger than 18 years old diagnosed with neoplasm, 95% of which were from Ribeirão Preto, SP, Brazil, and the remainder from cities located in all five of the Brazilian regions. Identifying the characteristics of patients contributes to the identification of information to broaden the sensitization of health professionals concerning the need for secondary preventive actions, such as early diagnosis.Este estudio tuvo por objetivo caracterizar las internaciones hospitalarias de niños y adolescentes con neoplasias, de 1998 a 2008, para conocer la clientela en seguimiento en la Regional de Salud de Ribeirao Preto, Sao Paulo, Brasil. Se realizó un levantamiento de la morbilidad en Ribeirao Preto, utilizando, como fuente de información, las internaciones hospitalarias por el Sistema Único de Salud. Las variables estudiadas fueron: procedencia, residencia, año de la atención, muertes, edad y sexo de los pacientes con diagnóstico de neoplasia infanto-juvenil, según el Capítulo II de la Clasificación Internacional de Enfermedades 10ª edición. Se constataron 7.234 internaciones de menores de 18 años con diagnóstico de neoplasias, de estas, 95% ocurrieron en Ribeirao Preto y las otras en municipios de procedencia pertenecientes a las cinco regiones del país. Conocer las características de la clientela atendida contribuye para identificar informaciones que pueden ampliar el proceso de sensibilización de los profesionales de salud para la necesidad de realizar acciones de prevención secundaria, como el diagnóstico precoz.Este estudo objetivou caracterizar as internações hospitalares de crianças e adolescentes com neoplasias, ocorridas de 1998 a 2008, para conhecer a clientela em seguimento na Regional de Saúde de Ribeirão Preto, SP, Brasil. Realizou-se levantamento da morbidade nesse município, utilizando-se, como fonte de informação, as internações hospitalares pelo Sistema Único de Saúde. As variáveis estudadas foram: procedência, residência, ano do atendimento, óbitos, idade e sexo dos pacientes com diagnóstico de neoplasia infantojuvenil, segundo o Capítulo II da Classificação Internacional de Doenças, 10ª edição. Evidenciaram-se 7.234 internações de menores de 18 anos com diagnóstico de neoplasias; dessas, 95% eram de Ribeirão Preto, SP, Brasil, e o restante procedentes de municípios das cinco regiões do país. Conhecer as características da clientela atendida contribui para a identificação de informações que podem ampliar o processo de sensibilização dos profissionais de saúde, para a necessidade de ações de prevenção secundária, como o diagnóstico precoce

    Nonlinear Coherence Effects in Transient-Absorption Ion Spectroscopy with Stochastic Extreme-Ultraviolet Free-Electron Laser Pulses

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    We demonstrate time-resolved nonlinear extreme-ultraviolet absorption spectroscopy on multiply charged ions, here applied to the doubly charged neon ion, driven by a phase-locked sequence of two intense free-electron laser pulses. Absorption signatures of resonance lines due to 2pp--3dd bound--bound transitions between the spin-orbit multiplets 3^3P0,1,2_{0,1,2} and 3^3D1,2,3_{1,2,3} of the transiently produced doubly charged Ne2+^{2+} ion are revealed, with time-dependent spectral changes over a time-delay range of (2.4±0.3)fs(2.4\pm0.3)\,\text{fs}. Furthermore, we observe 10-meV-scale spectral shifts of these resonances owing to the AC Stark effect. We use a time-dependent quantum model to explain the observations by an enhanced coupling of the ionic quantum states with the partially coherent free-electron-laser radiation when the phase-locked pump and probe pulses precisely overlap in time

    Strong-field extreme-ultraviolet dressing of atomic double excitation

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    We report on the experimental observation of strong-field dressing of an autoionizing two-electron state in helium with intense extreme-ultraviolet laser pulses from a free-electron laser. The asymmetric Fano line shape of this transition is spectrally resolved, and we observe modifications of the resonance asymmetry structure for increasing free-electron-laser pulse energy on the order of few tens of μ\muJ. A quantum-mechanical calculation of the time-dependent dipole response of this autoionizing state, driven by classical extreme-ultraviolet (XUV) electric fields, reveals a direct link between strong-field-induced energy and phase shifts of the doubly excited state and the Fano line-shape asymmetry. The experimental results obtained at the Free-Electron Laser in Hamburg (FLASH) thus correspond to transient energy shifts on the order of few meV, induced by strong XUV fields. These results open up a new way of performing non-perturbative XUV nonlinear optics for the light-matter interaction of resonant electronic transitions in atoms at short wavelengths

    Evolutionary and pulsational properties of white dwarf stars

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    Abridged. White dwarf stars are the final evolutionary stage of the vast majority of stars, including our Sun. The study of white dwarfs has potential applications to different fields of astrophysics. In particular, they can be used as independent reliable cosmic clocks, and can also provide valuable information about the fundamental parameters of a wide variety of stellar populations, like our Galaxy and open and globular clusters. In addition, the high densities and temperatures characterizing white dwarfs allow to use these stars as cosmic laboratories for studying physical processes under extreme conditions that cannot be achieved in terrestrial laboratories. They can be used to constrain fundamental properties of elementary particles such as axions and neutrinos, and to study problems related to the variation of fundamental constants. In this work, we review the essentials of the physics of white dwarf stars. Special emphasis is placed on the physical processes that lead to the formation of white dwarfs as well as on the different energy sources and processes responsible for chemical abundance changes that occur along their evolution. Moreover, in the course of their lives, white dwarfs cross different pulsational instability strips. The existence of these instability strips provides astronomers with an unique opportunity to peer into their internal structure that would otherwise remain hidden from observers. We will show that this allows to measure with unprecedented precision the stellar masses and to infer their envelope thicknesses, to probe the core chemical stratification, and to detect rotation rates and magnetic fields. Consequently, in this work, we also review the pulsational properties of white dwarfs and the most recent applications of white dwarf asteroseismology.Comment: 85 pages, 28 figures. To be published in The Astronomy and Astrophysics Revie

    Measurements of fiducial and differential cross sections for Higgs boson production in the diphoton decay channel at s√=8 TeV with ATLAS

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    Measurements of fiducial and differential cross sections are presented for Higgs boson production in proton-proton collisions at a centre-of-mass energy of s√=8 TeV. The analysis is performed in the H → γγ decay channel using 20.3 fb−1 of data recorded by the ATLAS experiment at the CERN Large Hadron Collider. The signal is extracted using a fit to the diphoton invariant mass spectrum assuming that the width of the resonance is much smaller than the experimental resolution. The signal yields are corrected for the effects of detector inefficiency and resolution. The pp → H → γγ fiducial cross section is measured to be 43.2 ±9.4(stat.) − 2.9 + 3.2 (syst.) ±1.2(lumi)fb for a Higgs boson of mass 125.4GeV decaying to two isolated photons that have transverse momentum greater than 35% and 25% of the diphoton invariant mass and each with absolute pseudorapidity less than 2.37. Four additional fiducial cross sections and two cross-section limits are presented in phase space regions that test the theoretical modelling of different Higgs boson production mechanisms, or are sensitive to physics beyond the Standard Model. Differential cross sections are also presented, as a function of variables related to the diphoton kinematics and the jet activity produced in the Higgs boson events. The observed spectra are statistically limited but broadly in line with the theoretical expectations

    Evidence for the h_b(1P) meson in the decay Upsilon(3S) --> pi0 h_b(1P)

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    Using a sample of 122 million Upsilon(3S) events recorded with the BaBar detector at the PEP-II asymmetric-energy e+e- collider at SLAC, we search for the hb(1P)h_b(1P) spin-singlet partner of the P-wave chi_{bJ}(1P) states in the sequential decay Upsilon(3S) --> pi0 h_b(1P), h_b(1P) --> gamma eta_b(1S). We observe an excess of events above background in the distribution of the recoil mass against the pi0 at mass 9902 +/- 4(stat.) +/- 2(syst.) MeV/c^2. The width of the observed signal is consistent with experimental resolution, and its significance is 3.1sigma, including systematic uncertainties. We obtain the value (4.3 +/- 1.1(stat.) +/- 0.9(syst.)) x 10^{-4} for the product branching fraction BF(Upsilon(3S)-->pi0 h_b) x BF(h_b-->gamma eta_b).Comment: 8 pages, 4 postscript figures, submitted to Phys. Rev. D (Rapid Communications

    Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

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    The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

    Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector

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    The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +c¯¯)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−s¯¯¯ quark asymmetry

    Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

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    The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30
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