Estudo teórico da contribuição à dose de partículas secundárias geradas por Prótons de energias entre 100 e 200 MeV num Phantom de osso cortical

In proton therapy, the deposition of secondary particles energy originated by nuclear inelastic process (n, 2H, 3H, 3He and α) has a contribution in the total dose that deserves to be discussed. In calculations of plans implemented for routine treatment, the paid dose is calculated whereas the proton loses energy by ionization and or coulomb excitement. The contribution of inelastic processes associated with nuclear reactions is not considered. There are only estimates for pure materials or simple composition (water, for example), because of the difficulty of processing targets consisting of different materials. For this project, we use the Monte Carlo method employing the code MCNPX v2.50 (Monte Carlo N-Particle eXtended) to present results of the contribution to the total dose of secondary particles. In this work, it was implemented a cylindrical phantom composed by cortical bone, for proton beams between 100 and 200 MeV. With the results obtained, it was possible to generate graphics to analyze: the dose deposition relation with and without nuclear interaction, the multiplicity and percentage of deposited dose for each secondary particle and a radial dispersion of neutrons in the material

Associação entre posicionamento do aluno na sala de aula e desempenho escolar

This research was aimed at analyzing whether there is an association between the positioning of the pupil in the classroom and his academic performance, as well as to diagnose the main factors underlying the association. Thus, this study analyzed 4 Elementary School II institutions of both public and private educational systems, in Botucatu, São Paulo, Brazil during a school year bimester. To register the positions students were seated, 29 similar classes (containing 6 rows x 6 columns) were investigated, each one with around 30 students, which resulted in a sampling of 859 students. For the questionnaire application, which objective was to verify the main reason for students’ seat choice, the same 29 classes were investigated. However, the sampling number was reduced to 692 students. In turn, for the collection of school performance and absence percentage of each student for the bimester in question, teachers’ evaluation books were used. As a result, it was found that the lower the percentage of the student's absences, the greater is their performance at school, and the greater their performance at school is, the closer up front to the board they are seated. Finally, the closer up to the board they are seated, the more their motivation and interest in learning increase. Therefore, there is an association between the position of a student in the classroom and his or her academic performance, where the association is conditioned by the motivation and interest in learning

Estudo teórico da contribuição a dose de partículas secundárias geradas por prótons de energias entre 100-200 MeV num phantom de osso compacto

The contribution of the total dose due to deposition of secondary energy particles caused by nuclear inelastic processes (n, 2H, 3H, 3He and  ) in proton therapy is an opened problem and in discussion. In the calculations of plans implemented for routine treatment, the paid dose is calculated whereas that the proton loses energy by ionization and or coulomb excitement. The contribution of inelastic processes associated with nuclear reactions is not considered, mainly due to the difficulty of processing targets consisting of various materials. In this sense, there are only estimates for pure materials or simple composition (water, for example).This work presents the results of simulations by the Monte Carlo method employing the code MCNPX v2.50 (Monte Carlo N-Particle eXtended) of the contribution to the total dose of secondary particles. The study was implemented in a cylindrical phantom composed by compact bone, for monochromatic beams of protons between 100 and 200 MeV with pencil beam form