Quantum mechanics of higher derivative systems and total derivative terms

A general theory is presented of quantum mechanics of singular, non-autonomous, higher derivative systems. Within that general theory, $n$-th order and $m$-th order Lagrangians are shown to be quantum mechanically equivalent if their difference is a total derivative.Comment: 14 pages, REVTeX, no figure

The Fractal Dimension of the Spectrum of the Fibonacci Hamiltonian

We study the spectrum of the Fibonacci Hamiltonian and prove upper and lower bounds for its fractal dimension in the large coupling regime. These bounds show that as $\lambda \to \infty$, $\dim (\sigma(H_\lambda)) \cdot \log \lambda$ converges to an explicit constant ($\approx 0.88137$). We also discuss consequences of these results for the rate of propagation of a wavepacket that evolves according to Schr\"odinger dynamics generated by the Fibonacci Hamiltonian.Comment: 23 page

Generalized Vaidya Solutions

A large family of solutions, representing, in general, spherically symmetric Type II fluid, is presented, which includes most of the known solutions to the Einstein field equations, such as, the monopole-de Sitter-charged Vaidya ones.Comment: Gen. Relativ. Grav. 31 (1), 107-114 (1999

The causal structure of dynamical charged black holes

We study the causal structure of dynamical charged black holes, with a sufficient number of massless fields, using numerical simulations. Neglecting Hawking radiation, the inner horizon is a null Cauchy horizon and a curvature singularity due to mass inflation. When we include Hawking radiation, the inner horizon becomes space-like and is separated from the Cauchy horizon, which is parallel to the out-going null direction. Since a charged black hole must eventually transit to a neutral black hole, we studied the neutralization of the black hole and observed that the inner horizon evolves into a space-like singularity, generating a Cauchy horizon which is parallel to the in-going null direction. Since the mass function is finite around the inner horizon, the inner horizon is regular and penetrable in a general relativistic sense. However, since the curvature functions become trans-Planckian, we cannot saymore about the region beyond the inner horizon, and it is natural to say that there is a 'physical' space-like singularity. However, if we assume an exponentially large number of massless scalar fields, our results can be extended beyond the inner horizon. In this case, strong cosmic censorship and black hole complementarity can be violated.Comment: 23 pages, 23 figure

O perfil de um grupo de pessoas hipertensas de acordo com conhecimento e gravidade da doença

We interviewed 205 hypertensives to characterize social demographic data, life style, history and awareness of hypertension. Most patients were female (72%), white (63%), over 40 years old (78%), married (60%), and had low level of education (68%). Their family income was lower than US$ 3000 a year (41%). In terms of weight, 75% were classified as overweight, 76% were non smoker, and 89% did not do any regular physical activity. The profile of the hypertensives who were unaware of the disease was: male, 20-40 years old, widow, not white, and non-obese. The profile of the hypertensives who had high level of hypertension (diastólic>; 110 mm Hg) was older than 60 years old, not married, overweight, low level of education, low income, with more than 5 years of hypertension, and previously treated.Foram entrevistados 205 hipertensos em tratamento ambulatorial para avaliar o papel do perfil bio-social no conhecimento e grau de gravidade da doença. As características da população foram: 72% mulheres, 63% brancos, 78% com mais de 40 anos, 60% casados, 68% com baixa escolaridade, 41% com renda de 1 a 3 salários, 75% com peso elevado, 76% não fumantes, 89% sem atividade física regular, e das mulheres 48% já tinham usado hormônios anticoncepcionais. A análise evidenciou que a ausência de conhecimento se associou com sexo masculino, idade entre 20 e 40 anos, viúvo, não branco e peso normal. Pressão arterial mais elevada (diastólica>; 110 mm Hg) se associou com mais de 60 anos, não casado, acima do peso, baixa escolaridade, baixa renda, com mais de 5 anos de hipertensão e já ter feito tratamento anterior