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Rio de Janeiro, Brazil

Thome R.C.A.,CEFET RJ | Yang H.M.,University of Campinas | Esteva L.,National Autonomous University of Mexico
Mathematical Biosciences | Year: 2010

We present a mathematical model to describe the dynamics of mosquito population when sterile male mosquitoes (produced by irradiation) are introduced as a biological control, besides the application of insecticide. In order to analyze the minimal effort to reduce the fertile female mosquitoes, we search for the optimal control considering the cost of insecticide application, the cost of the production of irradiated mosquitoes and their delivery as well as the social cost (proportional to the number of fertilized females mosquitoes). The optimal control is obtained by applying the Pontryagin's Maximum Principle. © 2009 Elsevier Inc. All rights reserved. Source

Vignoli L.L.,Pontifical Catholic University of Rio de Janeiro | Kenedi P.P.,CEFET RJ
Latin American Journal of Solids and Structures | Year: 2016

A human femur model, submitted to static loads, is analyzed through the utilization of three material constitutive relationships, namely: isotropic, transversally isotropic and orthotropic. The influence of bone anisotropy with respect to principal stress/strain distribution on human femur external surface was accessed through the use of analytical and finite element approaches. The models results show that the principal angles at a medial path bone surface have a good correlation with human femur bone lamellae angles. © 2016, Brazilian Association of Computational Mechanics. All rights reserved. Source

Andrade D.P.P.,University of Paraiba Valley | De barros A.L.F.,CEFET RJ | Pilling S.,University of Paraiba Valley | Domaracka A.,CNRS Center for Research on Ions, Materials and Photonics | And 3 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2013

We studied the effects produced by the interaction of heavy ion cosmic rays with interstellar and cometary organic molecules in the solid phase. Formic acid (HCOOH) ice at 15 K was irradiated by 267-MeV 56Fe22+ ions and the chemical evolution was analysed using Fourier transform infrared spectroscopy. The destruction cross-section of HCOOH and the formation cross-sections of the produced molecular species have been determined; the sputtering yield values are also discussed. The most abundant chemical species formed by Fe ion irradiation are CO, CO2 and H2O. The half-life of frozen formic acid molecules in the interstellar medium, as a result of interaction with the different cosmic ray constituents, is evaluated to be 108 yr, considering that the destruction cross-section σd of heavy ions is ruled by a power law as a function of the electronic stopping power Se (i.e. σd ∼ S3/2 e). Moreover, a complementary study based on mass spectrometry data from the literature has been performed, in order to understand the HCOOH molecule radiolysis, the desorption of its product and the chemical reaction pathways in ice. © 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Source

De Barros A.L.F.,CEFET RJ | De Barros A.L.F.,CNRS Center for Research on Ions, Materials and Photonics | Domaracka A.,CNRS Center for Research on Ions, Materials and Photonics | Andrade D.P.P.,University of Paraiba Valley | And 3 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2011

The chemical and physical effects induced by fast heavy ion irradiation on frozen pure methanol (CH3OH) at 15K were studied. These energetic ions can simulate the energy transfer processes that occur by cosmic ray irradiation of interstellar ices, comets and icy Solar system bodies. The analysis was made by infrared spectroscopy (Fourier transform infrared) before and after irradiation, with 16-MeV 16O5+, 220-MeV 16O7+, 606-MeV 65Zn20+ and 774-MeV 86Kr31+ ion beams. Integrated values of the absorbance of the main methanol bands were determined. The induced CH3OH dissociation gives rise to the formation of molecular species, particularly H2CO, CH2OH, CH4, CO, CO2, HCO and HCOOCH3. Their formation and dissociation cross-sections were determined. H2CO and CH4 molecules are in general the most abundant new products of the four beams analysed. Except for the HCO and CH2OH species, cross-sections increased with the electronic stopping power, roughly as σ∼S3/2 e. The G values for CH3OH destruction by fast heavy ion irradiation with Zn and Kr beams were found to be considerably larger than those for oxygen, helium or hydrogen. As an astrophysical implication, the S3/2 e power law should be very helpful for predicting the CH3OH formation and dissociation cross-sections for other ion beam projectiles and energies. As astrophysical point of view, the analysis of the predictions reveals the unexpected importance of iron and some other heavy ion constituents of cosmic rays in astrochemistry. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS. Source

Professional Master's Programs present major difficulties in their evaluations, since they are the newest modality of stricto sensu graduate program in Brazil. This work presents a methodology to evaluate perceptions on the impact of a Professional Master's Program on the skills of its alumni and on academic aspects of the course implementation. The methodology was applied in a specific situation collecting perceptions from both alumni and their bosses in the organization about the influence of the Master's Program on graduates' skills. Results showed that the respondents have perceived 'self-esteem' and 'researcher's profile' as the skills that were most positively influenced by the program. Source

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