Neutron Activation Analysis of Microleakage Around a Hydrophobic Composite Restorative

Neutron activation analysis with dysprosium as a tracer was employed to determine quantitatively the microleakage around the restorations of an experimental hydrophobic composite, as well as a commercial composite. Only a negligible uptake of tracer was obtained for the experimental composite, whereas a five-fold uptake was recorded for the commercial composite. Capillary penetration of fluid around a restoration could be greatly reduced by using a hydrophobic composite.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68248/2/10.1177_00220345800590090901.pd

Deconstruction, Lattice Supersymmetry, Anomalies and Branes

We study the realization of anomalous Ward identities in deconstructed (latticized) supersymmetric theories. In a deconstructed four-dimensional theory with N=2 supersymmetry, we show that the chiral symmetries only appear in the infrared and that the anomaly is reproduced in the usual framework of lattice perturbation theory with Wilson fermions. We then realize the theory on the world-volume of fractional D-branes on an orbifold. In this brane realization, we show how deconstructed theory anomalies can be computed via classical supergravity. Our methods and observations are more generally applicable to deconstructed/latticized supersymmetric theories in various dimensions.Comment: 1+27 pages, 2 figures, references adde

On the chirality of quark modes

A model for the QCD vacuum based on a domainlike structured background gluon field with definite duality attributed to the domains has been shown elsewhere to give confinement of static quarks, a reasonable value for the topological susceptibility and indications that chiral symmetry is spontaneously broken. In this paper we study in detail the eigenvalue problem for the Dirac operator in such a gluon mean field. A study of the local chirality parameter shows that the lowest nonzero eigenmodes possess a definite mean chirality correlated with the duality of a given domain. A probability distribution of the local chirality qualitatively reproduces histograms seen in lattice simulations.Comment: RevTeX4, 5 figures, 14 page

Caracterização da produtividade do pinhão da espécie pinheiro manso (Pinus pinea L.) na região de Mirandela.

As áreas arborizadas com pinheiro manso (Pinus pinea L.) tem aumentado nos últimos anos devido ao rendimento do pinhão sendo necessário realizar estudos de caracterização da cultura para poder aplicar uma gestão adequada e maximizar a sua produtividade. Neste trabalho pretende-se cacterizar a produção de pinhão desta nova cultura na região de Mirandela. O trabalho foi realizado numa área de pinheiro manso com 40 hectares e cerca de 20 anos de idade. Foram colhidas aleatoriamente 37 pinhas pertencentes a 18 árvores. As pinhas foram avaliadas em termos de peso, dimensão e sanidade. Após a secagem das pinhas em estufa a 40°C, efetuou-se a contagem do número de pinhões por pinha. De cada pinha foi retirada uma amostra de 12 pinhões de forma aleatória para avaliar a sua sanidade e peso com e sem casca. Os resultados apontam para um número médio de 79 pinhões por pinha com 48% de viabilidade e uma taxa de ataque atribuída ao Leptoglossus occidentalis de cerca de 3%. Avaliou-se também o peso de 100 pinhões com casca e sem casca tendo-se obtido um aproveitamento em polpa de 27%. Em média são necessário 173 pinhões para obter 100g de pinhões sem casca e 620 pinhões para obter 100g de pinhão descascado. Assim, serão necessárias aproximadamente 16 pinhas para se obter 100g de pinhão descascado. Na região 1 kg de pinha corresponde a cerca de 3,6 pinhas o que está dentro dos valores referidos como padrão para a região Sul. Esta primeira análise de produtividade na região é bastante promissora para a expansão da cultura desta espécie na Terra Quente Transmontana.Financiado pelo FEADER e pelo Estado Português, no âmbito da Ação 1.1 “Grupos Operacionais” integrado na Medida 1. Inovação do PDR 2020.info:eu-repo/semantics/publishedVersio

Noncommuting Electric Fields and Algebraic Consistency in Noncommutative Gauge theories

We show that noncommuting electric fields occur naturally in $\theta$-expanded noncommutative gauge theories. Using this noncommutativity, which is field dependent, and a hamiltonian generalisation of the Seiberg-Witten Map, the algebraic consistency in the lagrangian and hamiltonian formulations of these theories, is established. A comparison of results in different descriptions shows that this generalised map acts as canonical transformation in the physical subspace only. Finally, we apply the hamiltonian formulation to derive the gauge symmetries of the action.Comment: 16 pages, LaTex, considerably expanded version with a new section on `Gauge symmetries'; To appear in Phys. Rev.

Localized Endomorphisms of the Chiral Ising Model

Based on the treatment of the chiral Ising model by Mack and Schomerus, we present examples of localized endomorphisms $\varrho_1^{\rm loc}$ and $\varrho_{1/2}^{\rm loc}$. It is shown that they lead to the same superselection sectors as the global ones in the sense that unitary equivalence $\pi_0\circ\varrho_1^{\rm loc}\cong\pi_1$ and $\pi_0\circ\varrho_{1/2}^{\rm loc}\cong\pi_{1/2}$ holds. Araki's formalism of the selfdual CAR algebra is used for the proof. We prove local normality and extend representations and localized endomorphisms to a global algebra of observables which is generated by local von Neumann algebras on the punctured circle. In this framework, we manifestly prove fusion rules and derive statistics operators.Comment: 41 pages, latex2

Expanded Strings in the Background of NS5-branes via a M2-brane, a D2-brane and D0-branes

Classical configurations of a M2-brane, a D2-brane and D0-branes are investigated in the background of an infinite array of M5-branes or NS5-branes. On the M2-brane, we discuss three kinds of configurations, such as a sphere, a cylinder and a torus-like one. These are stabilized by virtue of the background fluxes of M5-branes. The torus-like M2-brane configuration has winding and momentum numbers of 11th direction, and in terms of the type IIA superstring theory, this corresponds to a torus-like D2-brane with electric and magnetic fluxes on it. We also reproduce the same configuration from a non-abelian Born-Infeld action for D0-branes. It will be a construction of closed strings from D0-branes. An electric flux quantization condition on the D2-brane is also discussed in terms of D0-branes.Comment: 33 pages, 6 figures, references and footnote added, confusing expressions and introduction are improved, version to appear in JHE

Noncommutative Differential Calculus for D-brane in Non-Constant B Field Background

In this paper we try to construct noncommutative Yang-Mills theory for generic Poisson manifolds. It turns out that the noncommutative differential calculus defined in an old work is exactly what we need. Using this calculus, we generalize results about the Seiberg-Witten map, the Dirac-Born-Infeld action, the matrix model and the open string quantization for constant B field to non-constant background with H=0.Comment: 21 pages, Latex file, references added, minor modificatio

Solving matrix models using holomorphy

We investigate the relationship between supersymmetric gauge theories with moduli spaces and matrix models. Particular attention is given to situations where the moduli space gets quantum corrected. These corrections are controlled by holomorphy. It is argued that these quantum deformations give rise to non-trivial relations for generalized resolvents that must hold in the associated matrix model. These relations allow to solve a sector of the associated matrix model in a similar way to a one-matrix model, by studying a curve that encodes the generalized resolvents. At the level of loop equations for the matrix model, the situations with a moduli space can sometimes be considered as a degeneration of an infinite set of linear equations, and the quantum moduli space encodes the consistency conditions for these equations to have a solution.Comment: 38 pages, JHEP style, 1 figur