Estudo eletroquímico de Fe[Fe(CN)5NO] em eletrodo de pasta de grafite

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

Power losses analysis and cooling system design of three topologies of multilevel inverters

This paper presents the comparison of three topologies of multilevel inverters applied to drive an induction motor of 500 kVA/4.16 kV. The multilevel inverters analyzed are: a neutral point clamped inverter, a symmetrical cascaded multilevel inverter and a hybrid asymmetrical cascaded multilevel inverter. The performance indexes used in the comparison are total harmonic distortion, first order distortion factor, semiconductors power losses distribution and heat-sink volume. The comparison is developed with the purpose of finding the efficiency and the heat-sink volume where the three systems present the same output filter. ©2008 IEEE.

Comparação entre o ponto P6 (NEIGUAM), ondansetron e da associação de ambos na prevenção de náuseas e vômitos em cirurgia ortopédica de membros inferiores sob bloqueio subaracnoideo

Pós-graduação em Anestesiologia - FMB

Confinement of neutral fermions by a pseudoscalar double-step potential in 1+1 dimensions

The problem of confinement of neutral fermions in two-dimensional space-time is approached with a pseudoscalar double-step potential in the Dirac equation. Bound-state solutions are obtained when the coupling is of sufficient intensity. The confinement is made plausible by arguments based on effective mass and anomalous magnetic interaction. (C) 2003 Elsevier B.V. B.V. All rights reserved.

Scattering of neutral fermions by a pseudoscalar potential step in two-dimensional spacetime

The problem of scattering of neutral fermions in two-dimensional spacetime is approached with a pseudoscalar potential step in the Dirac equation. Some unexpected aspects of the solutions beyond the absence of Klein's paradox are presented. An apparent paradox concerning the uncertainty principle is solved by introducing the concept of effective Compton wavelength. Added plausibility for the existence of bound-state solutions in a pseudoscalar double-step potential found in a recent Letter is given. (C) 2003 Elsevier B.V. B.V. All rights reserved.

The peremptory influence of a uniform background for trapping neutral fermions with an inversely linear potential

The problem of neutral fermions subject to an inversely linear potential is revisited. It is shown that an infinite set of bound-state solutions can be found on the condition that the fermion is embedded in an additional uniform background potential. An apparent paradox concerning the uncertainty principle is solved by introducing the concept of effective Compton wavelength.

Bounded solutions of neutral fermions with a screened Coulomb potential

The intrinsically relativistic problem of a fermion subject to a pseudoscalar screened Coulomb plus a uniform background potential in two-dimensional space-time is mapped into a Sturm-Liouville. This mapping gives rise to an effective Morse-like potential and exact bounded solutions are found. It is shown that the uniform background potential determinates the number of bound-state solutions. The behaviour of the eigenenergies as well as of the upper and lower components of the Dirac spinor corresponding to bounded solutions is discussed in detail and some unusual results are revealed. An apparent paradox concerning the uncertainty principle is solved by recurring to the concepts of effective mass and effective Compton wavelength. (c) 2005 Elsevier B.V. All rights reserved.

Relativistic confinement of neutral fermions with a trigonometric tangent potential

The problem of neutral fermions subject to a pseudoscalar potential is investigated. Apart from the solutions for E = +/- mc(2), the problem is mapped into the Sturm-Liouville equation. The case of a singular trigonometric tangent potential (similar to tan gamma x) is exactly solved and the complete set of solutions is discussed in some detail. It is revealed that this intrinsically relativistic and true confining potential is able to localize fermions into a region of space arbitrarily small without the menace of particle-antiparticle production.

High Curie point CaBi2Nb2O9 thin films: A potential candidate for lead-free thin-film piezoelectrics

CaBi2Nb2O9 (CBNO) thin films deposited on platinum coated silicon substrates by the polymeric precursor method exhibited good structural, dielectric, and piezoelectric characteristics. Capacitance-voltage measurements indicated good ferroelectric polarization switching characteristics. Remanent polarization and drive voltage values were 4.2 mu C/cm(2) and 1.7 V for a maximum applied voltage of 10 V. The film has a piezoelectric coefficient d(33) equal to 60 pm/V, current density of 0.7 mu A/cm(2), and Curie temperature of 940 degrees C. The polar-axis-oriented CBNO is a promising candidate for use in lead-free high Curie point in ferroelectric and piezoelectric devices. (c) 2006 American Institute of Physics.

Fermi pseudo-potential and energy-dependent point interactions in one dimension

There are point interactions in one dimension that can be interpreted as self-adjoint extensions (SAEs) of the kinetic energy [KE] operator. Here, we report the results obtained in two recent papers cited in [1]. In the first, we consider point interactions in one dimension in the form of the Fermi pseudo-potential, in one and two-channel cases. In the second, we consider a new type of point interactions that are self-adjoint and effectively energy-dependent. © 2005 American Institute of Physics.

Potential microbiological contamination of effluents in poultry and swine abattoirs

Health risks in the effluents of seven swine abattoirs and of seven poultry abattoirs were evaluated with regard to environment degradation and to dissemination of pathogenic microorganisms during the rainy and dry seasons. Supply-water samples from affluents and effluents of the treatment systems at different sites within the abattoir processing system were analysed. Similarly, water samples from the three recipient sites (emission point, 100 m upstream, 100 m downstream) were also analysed. Temperature, free residual chlorine (FRC), total coliform bacteria, Escherichia coli, enterococci, identification and serotyping of salmonellae were assessed. Scalding is the most significant stage in the slaughtering chain (P<0.05) when temperature is taken into account. Temperatures Lit effluents and at the sampled sites in the water bodies accorded to state and federal legislation standards. Supply waters did not meet the standards for FRC and microbial count standards according to the Ministry of Health and within limits imposed by the Industrial and Sanitary Inspection Regulations for Animal Products. Feather plucking and evisceration in Poultry slaughter and the cleansing of carcasses and facilities in Poultry and swine slaughtering had the highest contamination impact. The three loci at the water bodies were above the microbiological standards for classes II and III sites, in conformity with Law 8468 of the state of São Paulo, Brazil and Conama. Salmonella was found at several sites during slaughter, at both types of abattoirs, including in the effluent treatment system. This showed that these sites were the dissemination sources of the microorganism.

Trapping neutral fermions with kink-like potentials

The intrinsically relativistic problem of neutral fermions subject to kink-like potentials (similar to tanh gamma x) is investigated and the exact bound-state solutions are found. Apart from the lonely hump solutions for E = +/- mc(2), the problem is mapped into the exactly solvable Sturm-Liouville problem with a modified Poschl-Teller potential. An apparent paradox concerning the uncertainty principle is solved by resorting to the concepts of effective mass and effective Compton wavelength. (c) 2005 Elsevier B.V. All rights reserved.

Propolis: Is there a potential for the development of new drugs?

Introduction: Propolis has plenty of biological and pharmacological properties and its mechanisms of action have been widely investigated in the last years, using different experimental models in vitro and in vivo. Researchers have been interested in the investigation of isolated compounds responsible for propolis action; however, there is lack of clinical research on the effects of propolis.Strategy and objectives: Since propolis-containing products have been marketed and humans have used propolis for different purposes, the goal of this review is to discuss the potential of propolis for the development of new drugs, by comparing data from the literature that suggest candidate areas for the establishment of drugs against tumors, infections, allergy, diabetes, ulcers and with immunomodulatory action.Conclusions: The efficacy of propolis in different protocols in vitro and in vivo suggests its therapeutic properties, but before establishing a strategy using this bee product, it is necessary to study: (a) the chemical nature of the propolis sample. (b) Propolis efficacy should be compared to well-established parameters, e.g. positive or negative controls in the experiments. Moreover, possible interactions between propolis and other medicines should be investigated in humans as well. (c) Clinical investigation is needed to evaluate propolis potential in patients or healthy individuals, to understand under which conditions propolis may promote health. Data point out the importance of this research field not only for the readers and researchers in the scientific community waiting for further clarification on the potential of propolis but also for the pharmaceutical industry that looks for new drugs. (C) 2010 Elsevier B.V. All rights reserved.

Solutions of the Fokker-Planck equation for a Morse isospectral potential

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Recursive renormalization of the singlet one-pion-exchange plus point-like interactions

The subtracted kernel approach is shown to be a powerful method to be implemented recursively in scattering equations with regular plus point-like interactions. The advantages of the method allows one to recursively renormalize the potentials, with higher derivatives of the Dirac-delta, improving previous results. The applicability of the method is verified in the calculation of the 1 So nucleon-nucleon phase-shifts, when considering a potential with one-pion-exchange plus a contact interaction and its derivatives. The S-1(0) renormalization parameters are fitted to the data. The method can in principle be extended to any derivative order of the contact interaction, to higher partial waves and to coupled channels. (c) 2005 Elsevier B.V. All rights reserved.