Inversion in the temperature coefficient of the optical path length close to the glass transition temperature in tellurite glasses

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Minimal volume regulation after shrinkage of red blood cells from five species of reptiles

Red blood cells (RBCs) from most vertebrates restore volume upon hypertonic shrinkage and the mechanisms underlying this regulatory volume increase (RVI) have been studied extensively in these cells. Despite the phylogenetically interesting position of reptiles, very little is known about their red cell function. The present study demonstrates that oxygenated RBCs in all major groups of reptiles exhibit no or a very reduced RVI upon -25% calculated hyperosmotic shrinkage. Thus, RBCs from the snakes Crotalus durissus and Python regius, the turtle Trachemys scripta and the alligator Alligator mississippiensis showed no statistically significant RVI within 120 min after shrinkage, while the lizard Tupinambis merianae showed 22% volume recovery after 120 min. Amiloride (10(-4) M) and bumetanide (10(-5) M) had no effect on the RVI in T merianae, indicating no involvement of the Na(+)/H(+) exchanger (NHE) or the Na(+)/K(+)/2Cl(-) co-transporter (NKCC) or insentive transporters. Deoxygenation of RBCs from A. mississippiensis and T merianae did not significantly affect RVI upon shrinkage. Deoxygenation per se of red blood cells from T merianae elicited a slow volume increase, but the mechanism was not characterized. It seems, therefore, that the RVI response based on NHE activation was lost among the early sauropsids that gave rise to modern reptiles and birds, while it was retained in mammals. An RVI response has then reappeared in birds, but based on activation of the NKCC. Alternatively, the absence of the RVI response may represent the most ancient condition, and could have evolved several times within vertebrates. (C) 2008 Elsevier B.V. All rights reserved.

Convexity of the extreme zeros of Gegenbauer and Laguerre polynomials

Let C-n(lambda)(x), n = 0, 1,..., lambda > -1/2, be the ultraspherical (Gegenbauer) polynomials, orthogonal. in (-1, 1) with respect to the weight function (1 - x(2))(lambda-1/2). Denote by X-nk(lambda), k = 1,....,n, the zeros of C-n(lambda)(x) enumerated in decreasing order. In this short note, we prove that, for any n is an element of N, the product (lambda + 1)(3/2)x(n1)(lambda) is a convex function of lambda if lambda greater than or equal to 0. The result is applied to obtain some inequalities for the largest zeros of C-n(lambda)(x). If X-nk(alpha), k = 1,...,n, are the zeros of Laguerre polynomial L-n(alpha)(x), also enumerated in decreasing order, we prove that x(n1)(lambda)/(alpha + 1) is a convex function of alpha for alpha > - 1. (C) 2002 Published by Elsevier B.V. B.V.

NONDEGENERATE UMBILICS, THE PATH FORMULATION and GRADIENT BIFURCATION PROBLEMS

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Minimal 3-3-1 model, lepton mixing and muonium-antimuonium conversion

The recent experimental results on neutrino oscillation and on muonium-antimuonium conversion require extension of the minimal 3-3-1 model. We review the constraints imposed on the model by these measurements and suggest a pattern of leptonic mixing, with charged leptons in a non-diagonal basis, which accounts for the neutrino physics and circumvents the tight muonium-antimuonium bounds on the model. We also illustrate a scenario where this pattern could be realized.

Dressed coordinates: the path-integral approach

The recently introduced dressed coordinates are studied in the path-integral approach. These coordinates are defined in the context of a harmonic oscillator linearly coupled to massless scalar field and it is shown that in this model the dressed coordinates appear as a coordinate transformation preserving the path-integral functional measure. The analysis also generalizes the sum rules established in a previous work. (c) 2006 Elsevier B.V. All rights reserved.

Path integrals on a flux cone

This paper considers the Schrodinger propagator on a cone with the conical singularity carrying magnetic flux (flux cone). Starting from the operator formalism, and then combining techniques of path integration in polar coordinates and in spaces with constraints, the propagator and its path integral representation are derived. The approach shows that effective Lagrangian contains a quantum correction term and that configuration space presents features of nontrivial connectivity.

Neutrino mixing and the minimal 3-3-1 model

In the minimal 3-3-1 model charged leptons come in a nondiagonal basis. Moreover, the Yukawa interactions of the model lead to a non-hermitian charged lepton mass matrix. In other words, the minimal 3-3-1 model presents a very complex lepton mixing. In view of this we check rigorously if the possible textures of the lepton mass matrices allowed by the minimal 3-3-1 model can lead or not to the neutrino mixing required by the recent experiments in neutrino oscillation.

Metric-scalar gravity with torsion and the measurability of the non-minimal coupling

The measurability of the non-minimal coupling is discussed by considering the correction to the Newtonian static potential in the semiclassical approach. The coefficient of the gravitational Darwin term (GDT) gets redefined by the non-minimal torsion scalar couplings. Based on a similar analysis of the GDT in the effective field theory approach to non-minimal scalar, we conclude that for reasonable values of the couplings the correction is very small.

A path integral approach to the full Dicke model with dipole-dipole interaction

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

DYNAMICAL SYMMETRY BREAKING IN A MINIMAL 3-3-1 MODEL

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Search for Higgs bosons of the minimal supersymmetric standard model in p(p)over-bar collisions at root s=1.96 TeV D0 Collaboration

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A new proposal for the picture changing operators in the minimal pure spinor formalism

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Search for Next-to-Minimal Supersymmetric Higgs Bosons in the h -> aa ->mu mu mu mu, mu mu tau tau Channels Using pp Collisions at s=1.96 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Scalar bosons in minimal and ultraminimal technicolor: Masses, trilinear couplings, and widths

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)