11,902 research outputs found

    Quasi-Topological Field Theories in Two Dimensions as Soluble Models

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    We study a class of lattice field theories in two dimensions that includes gauge theories. Given a two dimensional orientable surface of genus gg, the partition function ZZ is defined for a triangulation consisting of nn triangles of area ϵ\epsilon. The reason these models are called quasi-topological is that ZZ depends on gg, nn and ϵ\epsilon but not on the details of the triangulation. They are also soluble in the sense that the computation of their partition functions can be reduced to a soluble one dimensional problem. We show that the continuum limit is well defined if the model approaches a topological field theory in the zero area limit, i.e., ϵ0\epsilon \to 0 with finite nn. We also show that the universality classes of such quasi-topological lattice field theories can be easily classified. Yang-Mills and generalized Yang-Mills theories appear as particular examples of such continuum limits.Comment: 23 pages, 16 figures, uses psbox.te

    Fiscal sustainability and policy implications for the euro area.

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    In this paper we examine the sustainability of euro area public finances against the backdrop of population ageing. We critically assess the widely used projections of the Working Group on Ageing Populations (AWG) of the EU's Economic Policy Committee and argue that ageing costs may be higher than projected in the AWG reference scenario. Taking into account adjusted headline estimates for ageing costs, largely based upon the sensitivity analysis carried out by the AWG, we consider alternative indicators to quantify sustainability gaps for euro area countries. With respect to the policy implications, we assess the appropriateness of different budgetary strategies to restore fiscal sustainability taking into account intergenerational equity. Our stylised analysis based upon the lifetime contribution to the government's primary balance of different generations suggests that an important degree of pre-funding of the ageing costs is necessary to avoid shifting the burden of adjustment in a disproportionate way to future generations. For many euro area countries this implies that the medium-term targets defined in the context of the revised stability and growth pact would ideally need to be revised upwards to significant surpluses.Population Ageing ; Fiscal Sustainability ; Generational Accounting ; Medium-term Objectives for Fiscal Policy

    Are all maximally entangled states pure?

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    We study if all maximally entangled states are pure through several entanglement monotones. In the bipartite case, we find that the same conditions which lead to the uniqueness of the entropy of entanglement as a measure of entanglement, exclude the existence of maximally mixed entangled states. In the multipartite scenario, our conclusions allow us to generalize the idea of monogamy of entanglement: we establish the \textit{polygamy of entanglement}, expressing that if a general state is maximally entangled with respect to some kind of multipartite entanglement, then it is necessarily factorized of any other system.Comment: 5 pages, 1 figure. Proof of theorem 3 corrected e new results concerning the asymptotic regime include

    Sistemas de cultivo para rendimento elevado em trigo e o desafio das correlações indesejadas.

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    bitstream/CNPT-2010/40666/1/p-do48.pd

    Lipschütz ulcer and group A streptococcal tonsillitis

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    Lipschütz ulcers (LU) are non-sexually related genital ulcers, rarely reported. We describe a healthy 11-year-old girl, who presented with fever and a painful vulvar ulcer associated with erythematous tonsillitis. Throat swab test for Group A Streptococcus (GAS) was positive. She was treated with amoxicillin. Further investigation was negative, including Herpes Simplex virus DNA from ulcer swab and serology for Epstein-Barr virus, cytomegalovirus and Mycoplasma pneumoniae Antistreptolysin O titre was high. The ulcer healed in 2 weeks, with no recurrence in a 1 year follow-up period. The association of LU with GAS tonsillitis is very rare.info:eu-repo/semantics/publishedVersio

    Electron transfer driven decomposition of adenine and selected analogs as probed by experimental and theoretical methods

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    We report on a combined experimental and theoretical study of electron transfer induced decomposition of adenine and a selection of analogue molecules in collisions with potassium atoms (K). Time-of-flight negative ion mass spectra have been obtained in a wide collision energy range (6–68 eV in the centre-of-mass frame), providing a comprehensive investigation of the fragmentation patterns of purine, adenine, 9-methyl adenine, 6-dimethyl adenine and 2-D adenine. Following our recent communication about selective hydrogen loss from the transient negative ions (TNI) produced in these collisions [T. Dunha et al. J. Chem. Phys. 148, 021101 (2018)], this work focuses on the production of smaller fragment anions. In the low-energy part of the present range, several dissociation channels that are accessible in free electron attachment experiments are absent from the present mass spectra, notably NH2 loss from adenine and 9-methyl adenine. This can be understood in terms of a relatively long transit time of the K+ cation in the vicinity of the TNI tending to enhance the likelihood of intramolecular electron transfer. In this case, the excess energy can be redistributed through the available degrees of freedom inhibiting fragmentation pathways. Ab initio theoretical calculations were performed for 9-methyl adenine (9-mAd) and adenine (Ad) in the presence of a potassium atom and provided a strong basis for the assignment the lowest unoccupied molecular orbitals accessed in the collision process

    Características físico-químicas de raízes de mandioca brava (Manihot esculenta Crantz).

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    A caracterização e avaliação do Banco Ativo de Germoplasma (BAG) de mandioca é fundamental para a sua utilização mais eficiente nos trabalhos de melhoramento genético, portanto o objetivo deste trabalho foi caracterizar 15 genótipos de mandioca brava pertencentes ao BAG da Embrapa Amazônia Oriental. A caracterização físico-química é fator preponderante para a seleção de genótipos, pois permite definir quais genótipos apresentam características desejáveis. Após a colheita das raízes, estas passaram por lavagem, descasque e armazenamento até o momento de utilização nas analises físico-químicas percentual de proteínas variou de 0,1-0,7%; lipídios 0,3-2,1%; umidade 58,0- 65,2%; cinzas de 0,1-1,0%; fibras 0,9-1,9%, carboidratos 13,9-39,4%; acidez 1,1-2,7%; ph 6,3-6,8 e SST de 0,8-1,2. As diferenças encontradas nos resultados podem contribuir para seleção de genótipos promissores a serem utilizados em programas de melhoramento genético
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