2,715 research outputs found

    A semiclassical model of light mesons

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    The dominantly orbital state description is applied to the study of light mesons. The effective Hamiltonian is characterized by a relativistic kinematics supplemented by the usual funnel potential with a mixed scalar and vector confinement. The influence of two different finite quark masses and potential parameters on Regge and vibrational trajectories is discussed.Comment: 1 figur

    Filling and wetting transitions of nematic liquid crystals on sinusoidal substrates

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    Close to sinusoidal substrates, simple fluids may undergo a filling transition, in which the fluid passes from a dry to a filled state, where the interface remains unbent but bound to the substrate. Increasing the surface field, the interface unbinds and a wetting transition occurs. We show that this double-transition sequence may be strongly modified in the case of ordered fluids, such as nematic liquid crystals. Depending on the preferred orientation of the nematic molecules at the structured substrate and at the isotropic-nematic interface, the filling transition may not exist, and the fluid passes directly from a dry to a complete-wet state, with the interface far from the substrate. More interestingly, in other situations, the complete wetting transition may be prevented, and the fluid passes from a dry to a filled state, and remains in this configuration, with the interface always attached to the substrate, even for very large surface fields. Both transitions are only observed for a same substrate in a narrow range of amplitudes

    H1N1 disseminated infection in a 3-month-old boy

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    Earlier this year a new influenza virus emerged. In children, the clinical manifestations of H1N1 infection are similar to those reported during periods of seasonal influenza. We report on a 3-month-old boy with an upper respiratory tract infection who presented enteropathy, coagulopathy and encephalitis related to H1N1. The infection was confirmed in nasopharyngeal aspirate, stools and cerebrospinal fluid by real-time PCR. Treatment with oseltamivir was started.info:eu-repo/semantics/publishedVersio

    Pentaquarks in the Jaffe-Wilczek approximation

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    The masses of uuddsˉuudd\bar s , uudddˉuudd\bar d and uussdˉuuss\bar d pentaquarks are evaluated in a framework of both the Effective Hamiltonian approach to QCD and spinless Salpeter using the Jaffe--Wilczek diquark approximation and the string interaction for the diquark--diquark--antiquark system. The pentaquark masses are found to be in the region above 2 GeV. That indicates that the Goldstone boson exchange effects may play an important role in the light pentaquarks. The same calculations yield the mass of [ud]2cˉ[ud]^2\bar c pentaquark ∼\sim 3250 MeV and [ud]2bˉ[ud]^2\bar b pentaquark ∼\sim 6509 MeV.Comment: 14 pages, 2 tables, LaTeX2e. References correcte

    Structural and Microanalytical Studies of CrO2 Thin Films on c-Sapphire by High Resolution Electron Microscopy Methods

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    Chromium dioxide (CrO2) has been extensively used in the magnetic recording industry. However, it is its ferromagnetic half-metallic nature that has more recently attracted much attention, primarily for the development of spintronic devices. CrO2 is the only stoichiometric binary oxide theoretically predicted to be fully spin polarized at the Fermi level. It presents a Curie temperature of ∼ 396 K, i.e. well above room temperature, and a magnetic moment of 2 mB per formula unit. However an antiferromagnetic native insulating layer of Cr2O3 is always present on the CrO2 surface which enhances the CrO2 magnetoresistance and might be used as a barrier in magnetic tunnel junctions

    Quantum repeaters and quantum key distribution: analysis of secret key rates

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    We analyze various prominent quantum repeater protocols in the context of long-distance quantum key distribution. These protocols are the original quantum repeater proposal by Briegel, D\"ur, Cirac and Zoller, the so-called hybrid quantum repeater using optical coherent states dispersively interacting with atomic spin qubits, and the Duan-Lukin-Cirac-Zoller-type repeater using atomic ensembles together with linear optics and, in its most recent extension, heralded qubit amplifiers. For our analysis, we investigate the most important experimental parameters of every repeater component and find their minimally required values for obtaining a nonzero secret key. Additionally, we examine in detail the impact of device imperfections on the final secret key rate and on the optimal number of rounds of distillation when the entangled states are purified right after their initial distribution.Comment: Published versio

    Cardiopulmonary complications in a patient with bezoar

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    We report a case of a 17-year-old institutionalised male with a medical history of fragile X syndrome, bilateral congenital glaucoma, cataracts and pica disorder. He was transferred to our paediatric intensive care unit owing to respiratory failure and hypotension. On transoesophageal echocardiogram, he presented left atrium compression. A CT of the thorax and mediastinum revealed an unknown heterogeneous material in the lumen of the stomach and oesophagus, with a lung parenchyma suggestive of alveolar foreign material. Endoscopic evaluation showed diaper fragments inside the oesophagus and stomach. Fragmentation and suction of diaper material was made. Medical treatment was performed with inotropic support, conventional mechanical ventilation and antibiotics

    Punctuated equilibrium theory in Brazilian public policy: the case of Ceará

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    Este artigo faz uma análise do processo de decisão orçamental dos municípios do Estado do Ceará. Através deste estudo, procura-se perceber em que medida a distribuição dos orçamentos aos governos locais sofrem (ou não) variações. Já em um segundo momento, tenta-se depreender quais as receitas de cada um dos municípios (as variáveis independentes) que melhor descrevem e auxiliam a opção política de investimento local (esta será a variável dependente). Considerando o período de 2006 a 2010 e fazendo uso de um desenho de pesquisa de tipo transversal, conclui-se que nos governos locais do Ceará o investimento público apresenta períodos de estabilidade seguido por períodos de grande alteração dos orçamentos – confirmando a hipótese de pesquisa. Estas conclusões confirmam os pressupostos da teoria do equilíbrio pontuado. Conclui-se igualmente que o investimento público que vem sendo realizado é dependente das transferências que a União faz para os governos locais do Estado do Ceará e das receitas de capital. Face a estas condições, é pertinente equacionar até que nível e grau o endividamento pode ocorrer em virtude da escassez cada vez maior do financiamento público.This research aims to analyze the budget decision process in Ceará municipalities in order to understand in which way budget distributions change (or not) during the research period under consideration. This research also aims to understand which revenues (the independent variables) of each municipality better expla in the political choices for local government investments (the dependent variable). Making use of data from 2006 to 2010 and using a cross - sectional research design, the study concludes a stability in local government investments periods of stress where su ch investments have both positive and negative significant fluctuations – confirming our working hypothesis. These results confirm punctuated Equilibrium Theory assumptions and also find that local government public investment is dependent on money transfe rs from the central government and also from capital revenues. Thus, it is important to question to what degree public indebtedness should be allowed, due to a scarcity of public fundsinfo:eu-repo/semantics/publishedVersio
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