1. Disciplina de Pneumologia, Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo (SP) Brasil. 2. Editor-Chefe do JBP Jornal Brasileiro de Pneumologia, Brasília (DF) Brasil. The Portuguese word momento can be translated in a number of ways. It is first and foremost translated as “moment”, which has an eminently temporal connotation, indicatin...

The momentum operator for a particle in a box is represented by an infinite order Hermitian matrix P . Its square P 2 is well defined (and diagonal), but its cube P 3 is ill defined, because P P 2 6= P 2 P . Truncating these matrices to a finite order restores the associative law, but leads to other curious results. Classification 0260 (02.10.Sp)

The non self-adjointness of the radial momentum operator has been noted before by several authors, but the various proofs are incorrect. We give a rigorous proof that the n-dimensional radial momentum operator is not self-adjoint and has no selfadjoint extensions. The main idea of the proof is to show that this operator is unitarily equivalent to the momentum operator on L[(0,∞), dr] which is n...

Design optimization of cable-stayed bridges is a challenging optimization problem because a large number of variables is usually involved in the optimization process. For these structures the design variables are cross-sectional areas of the cables. In this study, an efficient metaheuristic algorithm namely, momentum search algorithm (MSA) is used to optimize the design of cable-stayed bridges....

This paper combines a comprehensive sample of intraday firm-level news arrivals with high-frequency price movements of individual stocks, thereby decomposing daily stock returns into news-driven and non-news driven components. Consistent with prior literature, we find that non-news driven return precedes a reversal. For news-driven return, however, we find strong evidence of return continuation...

A classical theory is developed which calculates the momentum transfer rate constant between an ion and a non-polar molecule. The model takes into consideration the effect of diffraction outside the capture limit on the rate constants. The theory is used to calculate momentum transfer rate constant for Cl- with trans-dichloroethylene and para-difluorobenzene. Theoretical results ...