698 research outputs found

    Percolation model for nodal domains of chaotic wave functions

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    Nodal domains are regions where a function has definite sign. In recent paper [nlin.CD/0109029] it is conjectured that the distribution of nodal domains for quantum eigenfunctions of chaotic systems is universal. We propose a percolation-like model for description of these nodal domains which permits to calculate all interesting quantities analytically, agrees well with numerical simulations, and due to the relation to percolation theory opens the way of deeper understanding of the structure of chaotic wave functions.Comment: 4 pages, 6 figures, Late

    Câncer de boca : expressão imuno-histoquímica de c-erbB-2, Bcl-2 e EGFR : estudo comparativo com leucoplasia e hiperplasia inflamatória

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    5 p.Anormalidades em genes que regulam a proliferação e morte celular podem provocar inúmeras doenças entre elas o carcinoma epidermóide de boca. Tem sido relatado que alterações genéticas nas células tumorais predizem a agressividade biológica dos tumores. Marcadores genéticos como c-erbB-2, Bcl-2 e EGFR são considerados indicadores promissores de prognósticos para as lesões cancerizáveis e as neoplasias. Objetivo: Avaliar a expressão imunohistoquímica das proteínas c-erbB-2, Bcl-2 e EGFR (oncoproteínas envolvidas na vias de proliferação celular). Material e Métodos: cento e cinco blocos de parafina contendo fragmentos de biopsias incisionais, sendo 54 de carcinomas epidermóides, 25 blocos de leucoplasias e 26 blocos de hiperlasias obtidos do Laboratório de Patologia de Boca da Universidade Federal de Mato Grosso do Sul (UFMS). A expressão das proteínas foi verificada através da técnica imunohistoquímica utilizando a estreptoavidina-biotina-peroxidase no Laboratório de Patologia da Universidade de Brasília (UNB). Resultados: Os resultados revelaram diferença estatisticamente significante da proteína EGFR para os carcinomas epidermóides de boca e para as demais proteínas não houve diferença estatisticamente significante entre as lesões. Conclusões: Os resultados sugerem que o EGFR pode ser utilizado como marcador em carcinoma de boca podendo contribuir para a progressão da neoplasia, porém, sendo insuficiente na predição da carcinogênese. __________________________________________________________________________________ SUMMARYAbnormalities in genes that regulate the proliferation and cell death can provoke many lesions as oral epidermal carcinoma. It has been related that genetic alterations in tumoral cells predict the biologic agressivity in the tumors. Genetic markers as cerbB-2, Bcl-2 and EGFR are considered indicators of prognostic to the pre-malignant lesions and neoplasias. Objective: to study in the fragments of incisional biopsy the expression of c-erbB-2, Bcl-2 and EGFR proteins. Materials and methods: 54 cases of epidermal carcinoma, 25 cases of neoplasias and 26 cases of hyperplasias obtained from Oral Pathology’s Laboratory of Federal University of Mato Grosso do Sul (UFMS). The used method was streptoavidin-biotinperoxidase in Patthology’s Laboratory of University Brasilia (UNB). Results: The results revealed positivity significant of EGFR proteins to the oral epidermal carcinoma and to the other one protein there was no statistical significant difference. Conclusions: The results suggest that EGFR can be used as a marking in oral epidermal carcinoma and can contribute to the progression of neoplasia, however, being insufficient to predict the carcinogenesis

    First Experimental Observation of Superscars in a Pseudointegrable Barrier Billiard

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    With a perturbation body technique intensity distributions of the electric field strength in a flat microwave billiard with a barrier inside up to mode numbers as large as about 700 were measured. A method for the reconstruction of the amplitudes and phases of the electric field strength from those intensity distributions has been developed. Recently predicted superscars have been identified experimentally and - using the well known analogy between the electric field strength and the quantum mechanical wave function in a two-dimensional microwave billiard - their properties determined.Comment: 4 pages, 5 .eps figure

    Random wave functions and percolation

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    Recently it was conjectured that nodal domains of random wave functions are adequately described by critical percolation theory. In this paper we strengthen this conjecture in two respects. First, we show that, though wave function correlations decay slowly, a careful use of Harris' criterion confirms that these correlations are unessential and nodal domains of random wave functions belong to the same universality class as non critical percolation. Second, we argue that level domains of random wave functions are described by the non-critical percolation model.Comment: 13 page

    Exploring the parameter space of MagLIF implosions using similarity scaling. I. Theoretical framework

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    Magneto-inertial fusion (MIF) concepts, such as the Magnetized Liner Inertial Fusion (MagLIF) platform [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014)], constitute a promising path for achieving ignition and significant fusion yields in the laboratory. The space of experimental input parameters defining a MagLIF load is highly multi-dimensional, and the implosion itself is a complex event involving many physical processes. In the first paper of this series, we develop a simplified analytical model that identifies the main physical processes at play during a MagLIF implosion. Using non-dimensional analysis, we determine the most important dimensionless parameters characterizing MagLIF implosions and provide estimates of such parameters using typical fielded or experimentally observed quantities for MagLIF. We then show that MagLIF loads can be "incompletely" similarity scaled, meaning that the experimental input parameters of MagLIF can be varied such that many (but not all) of the dimensionless quantities are conserved. Based on similarity-scaling arguments, we can explore the parameter space of MagLIF loads and estimate the performance of the scaled loads. In the follow-up papers of this series, we test the similar scaling theory for MagLIF loads against simulations for two different scaling "vectors", which include current scaling and rise-time scaling.Comment: 24 pages, submitted to Physics of Plasma

    Asymptotic behaviour of multiple scattering on infinite number of parallel demi-planes

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    The exact solution for the scattering of electromagnetic waves on an infinite number of parallel demi-planes has been obtained by J.F. Carlson and A.E. Heins in 1947 using the Wiener-Hopf method. We analyze their solution in the semiclassical limit of small wavelength and find the asymptotic behaviour of the reflection and transmission coefficients. The results are compared with the ones obtained within the Kirchhoff approximation

    Out-of-equilibrium relaxation of the Edwards-Wilkinson elastic line

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    We study the non-equilibrium relaxation of an elastic line described by the Edwards-Wilkinson equation. Although this model is the simplest representation of interface dynamics, we highlight that many (not though all) important aspects of the non-equilibrium relaxation of elastic manifolds are already present in such quadratic and clean systems. We analyze in detail the aging behaviour of several two-times averaged and fluctuating observables taking into account finite-size effects and the crossover to the stationary and equilibrium regimes. We start by investigating the structure factor and extracting from its decay a growing correlation length. We present the full two-times and size dependence of the interface roughness and we generalize the Family-Vicsek scaling form to non-equilibrium situations. We compute the incoherent cattering function and we compare it to the one measured in other glassy systems. We analyse the response functions, the violation of the fluctuation-dissipation theorem in the aging regime, and its crossover to the equilibrium relation in the stationary regime. Finally, we study the out-of-equilibrium fluctuations of the previously studied two-times functions and we characterize the scaling properties of their probability distribution functions. Our results allow us to obtain new insights into other glassy problems such as the aging behavior in colloidal glasses and vortex glasses.Comment: 33 pages, 16 fig

    Comparison of Solar Fine Structure Observed Simultaneously in Ly-{\alpha} and Mg II h

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    The Chromospheric Lyman Alpha Spectropolarimeter (CLASP) observed the Sun in H I Lyman-{\alpha} during a suborbital rocket flight on September 3, 2015. The Interface Region Imaging Telescope (IRIS) coordinated with the CLASP observations and recorded nearly simultaneous and co-spatial observations in the Mg II h&k lines. The Mg II h and Ly-{\alpha} lines are important transitions, energetically and diagnostically, in the chromosphere. The canonical solar atmosphere model predicts that these lines form in close proximity to each other and so we expect that the line profiles will exhibit similar variability. In this analysis, we present these coordinated observations and discuss how the two profiles compare over a region of quiet sun at viewing angles that approach the limb. In addition to the observations, we synthesize both line profiles using a 3D radiation-MHD simulation. In the observations, we find that the peak width and the peak intensities are well correlated between the lines. For the simulation, we do not find the same relationship. We have attempted to mitigate the instrumental differences between IRIS and CLASP and to reproduce the instrumental factors in the synthetic profiles. The model indicates that formation heights of the lines differ in a somewhat regular fashion related to magnetic geometry. This variation explains to some degree the lack of correlation, observed and synthesized, between Mg II and Ly-{\alpha}. Our analysis will aid in the definition of future observatories that aim to link dynamics in the chromosphere and transition region.Comment: Accepted by Ap

    Spectral properties of distance matrices

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    Distance matrices are matrices whose elements are the relative distances between points located on a certain manifold. In all cases considered here all their eigenvalues except one are non-positive. When the points are uncorrelated and randomly distributed we investigate the average density of their eigenvalues and the structure of their eigenfunctions. The spectrum exhibits delocalized and strongly localized states which possess different power-law average behaviour. The exponents depend only on the dimensionality of the manifold.Comment: 31 pages, 9 figure
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