Quantization of a six-dimensional Wess-Zumino model

We examine a six-dimensional Wess-Zumino model. The equations of motion are of the fourth order, implying two modes of propagation; a normal bradyonic mode and a tachyonic mode. The conserved fermion current is constructed. The component fields are quantized in such a way that the operator representing the supercharge is the generator of supersymmetry transformations. The quantization is complemented by the definition of the vacuum for both modes. The evaluation of vacuum expectation values leads to a Feynman propagator for the normal mode and a half-advanced and half-retarded propagator for the tachyon mode. Convolutions between these propagators show consistency with unitarity.Departamento de Físic

Quantization of a 4th-Order Wave Equation

The quantization of a scalar field obeying a fourth-order wave equation is described. Faster-than-light particles appearing in the process are treated as ghosts, with the wrong relation between spin and statistics. In this way, positive energy spectrum, as well as positive metric in Fock space are obtained. Finally, some implications of an interaction described by a Lagrangian symmetrized in the scalar fields are briefly discussed.Facultad de Ciencias ExactasComisión de Investigaciones Científicas de la provincia de Buenos Aire

Quantization of a 4th-Order Wave Equation

The quantization of a scalar field obeying a fourth-order wave equation is described. Faster-than-light particles appearing in the process are treated as ghosts, with the wrong relation between spin and statistics. In this way, positive energy spectrum, as well as positive metric in Fock space are obtained. Finally, some implications of an interaction described by a Lagrangian symmetrized in the scalar fields are briefly discussed.Facultad de Ciencias ExactasComisión de Investigaciones Científicas de la provincia de Buenos Aire

The Tachyon propagator

Following the canonical quantization procedure for a tachyon field, the usual Hamiltonian and the creation and annihilation operators are obtained. The observation that the mass hyperboloidp; 2−m2; =0 is one-sheeted, as opposed to the case of bradyons wherep; 2+m2; =0 is two-sheeted, leads to the construction of a base which is unbounded for negative as well as for positive energies. There is a zero-energy eigenfunction from which all other states can be constructed by repeated application of decreasing or increasing operators; within this Fock space the vacuum expectation value of the chronological product of field operators is shown to coincide with Cauchy’s principal-value Green’s function.Facultad de Ciencias Exacta

The Tachyon Field below the mass barrier

We consider a tachyon field whose Fourier components correspond to spatial momenta with modulus smaller than the mass parameter. The plane wave solutions have them a time evolution which is a real exponential. The field is quantized and the solution of the eigenvalue problem for the Hamiltonian leads to the evaluation of the vacuum expectation value of products of field operators. The propagator turns out to be half-advanced and half-retarded. This completes the proof [4] that the total propagator is the Wheeler Green function [4,7].Facultad de Ciencias Exacta

Consequências Cardiorrespiratórias do Cigarro Eletrônico: Perspectivas Atuais

This paper presents a comprehensive review of the cardiovascular impacts of electronic cigarette use, based on a critical analysis of the available scientific literature. The results highlight a variety of significant findings, including immediate acute effects such as increased heart rate and blood pressure after electronic cigarette use, as well as potential long-term adverse effects such as endothelial dysfunction and oxidative stress. While some studies suggest that electronic cigarettes may represent a less harmful alternative to conventional smoking, there is still considerable uncertainty regarding their long-term effects on cardiovascular health. These findings underscore the importance of further research to elucidate underlying mechanisms and inform public health policies and clinical practices related to electronic cigarette use.Este trabalho apresenta uma revisão abrangente dos impactos cardiovasculares do uso de cigarros eletrônicos, com base em uma análise crítica da literatura científica disponível. Os resultados destacam uma variedade de descobertas significativas, incluindo efeitos agudos imediatos, como aumento da frequência cardíaca e pressão arterial após o uso de cigarros eletrônicos, bem como potenciais efeitos adversos a longo prazo, como disfunção endotelial e estresse oxidativo. Embora alguns estudos sugiram que os cigarros eletrônicos podem representar uma alternativa menos prejudicial ao tabagismo convencional, ainda há incerteza considerável sobre seus efeitos a longo prazo na saúde cardiovascular. Essas descobertas destacam a importância de uma pesquisa adicional para elucidar os mecanismos subjacentes e informar políticas de saúde pública e práticas clínicas relacionadas ao uso de cigarros eletrônicos

Proceedings of the Third International Conference on NDE in Relation to Structural Integrity for Nuclear Pressurized Components, 14-16 November 2001, Sevilla, Spain.

Abstract not availableJRC.F-Institute for Energy (Petten

Quantization of a six-dimensional Wess-Zumino model

We examine a six-dimensional Wess-Zumino model. The equations of motion are of the fourth order, implying two modes of propagation; a normal bradyonic mode and a tachyonic mode. The conserved fermion current is constructed. The component fields are quantized in such a way that the operator representing the supercharge is the generator of supersymmetry transformations. The quantization is complemented by the definition of the vacuum for both modes. The evaluation of vacuum expectation values leads to a Feynman propagator for the normal mode and a half-advanced and half-retarded propagator for the tachyon mode. Convolutions between these propagators show consistency with unitarity.Departamento de Físic