698 research outputs found
Low level of virological failure and drug resistance among patients receiving antiretroviral treatment under programme conditions in Maputo, Mozambique
Mexico AIDS Conference 200
Percolation model for nodal domains of chaotic wave functions
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-histoquÃmica de c-erbB-2, Bcl-2 e EGFR : estudo comparativo com leucoplasia e hiperplasia inflamatória
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 imunohistoquÃmica das proteÃnas c-erbB-2, Bcl-2 e EGFR (oncoproteÃnas 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 proteÃnas foi verificada através da técnica imunohistoquÃmica utilizando a estreptoavidina-biotina-peroxidase no Laboratório de Patologia da Universidade de BrasÃlia (UNB). Resultados: Os resultados revelaram diferença estatisticamente significante da proteÃna EGFR para os carcinomas epidermóides de boca e para as demais proteÃnas 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
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
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
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
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
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
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
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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