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Item Freya: an educational MATLAB GUI-based tool for generalized Fourier series(Research, Society and Development) Macedo, Humberto Gimenes; Oliveira, Virgínia Klausner de; Gomes, Anna Karina Fontes; Fernandes, Francisco Carlos RochaThe Fourier analysis is a very powerful mathematical tool to decompose functions into their frequency components. Due to this, it has applications in a wide variety of fields inside the realm of science and engineering. As usual, this theory starts with a discussion about the trigonometric Fourier series, the expansion of a function in terms of sines and cosines, and then is generalized in the sense that other functions rather than the trigonometric ones can be used as an orthogonal basis, as the eigenfunctions of some specific Sturm-Liouville problems, such as Bessel functions and Legendre polynomials. In this direction, we present the so- called Freya, an educational graphical user interface (GUI) for the generalized Fourier series developed using the interactive MATLAB (MATrix Laboratory) App Designer environment. We aim to provide a user-friendly tool as a learning aid system for students to gain a comprehensive understanding of the subject as well as for teaching.Item Enhancing learning of the Grad-Shafranov equation through scientific literature: part 2 of a physics education series(Sociedade Brasileira de Física) Santos, Lenadro Nunes dos; Ojeda González, Arian; La Luz, Victor Hugo de; Oliveira, Virgínia Klausner de; Pilling, Sergio; Prestes, Alan; Sousa, Antonio Nilson Laurindo; Oliveira, Matheus Felipe Cristaldo deIn part 1 of our physics education series, we introduced a novel solution based on Yoon-Lui’s solutions 1 and 2. Building upon that, this follow-up presents a new solution obtained by combining the generating functions of Yoon-Lui-1 and Yoon-Lui-3, resulting in a new and simplified general solution. We also calculate the singular points and determine their coordinates for various parameter values. A graphical representation of the solution is presented, showing the magnetic field lines and current density distribution. The behavior of the magnetic field and the effect of varying the parameter are discussed. The observed magnetic islands and singular points are relevant in the fields of Plasma Physics and Space Physics, providing insights into magnetic structures in plasmas and their impact on confinement and stability. Furthermore, this study encourages innovation and equips researchers and students with the necessary tools to make meaningful contributions to the field, emphasizing the integration of scientific literature into physics education to promote a comprehensive understanding of physical concepts and their practical applications.Item Análise de componentes principais aplicada à dendrocronologiaSilva, Daniela Oliveira da; Oliveira, Virgínia Klausner de; Prestes, Alan; Macedo, Humberto GimenesItem Analysis of Y-component of geomagnetic field and SYM-H Index using wavelet multiresolution analysis(Springer Nature Link) Sapkota, Santosh; Saurav, Sarup Khadka; Gautam, Sabin; Karki, Monika; Adhikari, Binod; Mishra, Roshan Kumar; Oliveira, Virgínia Klausner de; Dhungana, Beni MadhavElectrodynamical coupling between the solar wind’s plasma and the Earth’s magnetosphere cre- ates geomagnetic disturbances recorded on the ground. This work analyzes the Y-component of the geomag- netic field during two geomagnetic storms and compares it to the solar quiet days. The magnetogram data recorded on low latitude stations are used for the study. We investigated the correlation of the Y-component with geomagnetic index SYM-H using wavelet multiresolution analysis. We have used solar wind velocity, pressure, and interplanetary magnetic fields (By and Bz) to know the interplanetary structure for the selected duration. We found a positive correlation between Y-component and the SYM-H index for both events. The magnitude of the Y-component was significantly reduced during the main phase in comparison to the quiet days. Further, variation of solar wind parameters indicated geomagnetic storms are guided by the prolonged southward IMF-Bz component and highly fluctuated IMF-By component. This work connects the inter- planetary plasma parameters to the storm-time geomagnetic variations.Item Ahead-of-Tsunami magnetic disturbance detection using intrinsic mode functions: Tohoku-Oki earthquake case study(Springer Nature Link) Oliveira, Virgínia Klausner de; Macedo, Humberto Gimenes; Prestes, AlanWe document magnetic disturbances that occurred during the Tohoku-Oki tsunami of 11 March 2011 using empirical mode decomposition (EMD) in a dataset derived from a network of ground-based magnetometers (INTERMAGNET and GIS). The disturbances, obtained by filtering the magnetic field data using the first intrinsic mode function (IMF1) of EMD, propagate ahead of the tsunami at a speed in the range of 600–1.6 km/s. They also appear 3 min (near-field) to 2 h (far-field) earlier than the tsunami arrival at the magnetic observatories. We refer to these distur- bances as ahead-of-tsunami magnetic disturbances (ATMDs). A comparison with seismometer data shows them arriving 10 min after the arrival of Rayleigh waves. Their association with both seismogenic and tsunamigenic processes is discussed, and it is argued that the tsunamigenic process can well explain the magnetic disturbance propagation characteristics at the far-field. At near- field, the ATMDs are the coseismic magnetic signatures mainly driven by surface Rayleigh waves. Monitoring these ATMDs can be extremely useful for the early warning of the tsunami.Item Reabilitação sensório-motora associada à fotobiomodulação transcraniana em pacientes com lesão do sistema nervoso central(Revista Univap) Guimarães, Carolina Lobo; Pinto, Ana Paula; Macedo, Humberto Gimenes; Oliveira, Virgínia Klausner de; Lima, Fernanda Púpio Silva; Lopes-Martins, Rodrigo Álvaro Brandão; Lima, Mário OliveiraAs doenças neurológicas geralmente estão associadas a importantes déficits funcionais, dificultando a execução de atividades de vida diária e autocuidado. Pesquisas recentes demonstram efeitos positivos da Fotobiomodulação Transcraniana (FBM-T) para estimulação do tecido cerebral. O estudo teve como objetivo avaliar os efeitos da FBM-T associada ao treinamento aeróbico na função do sistema musculoesquelético de indivíduos com lesões neurológicas crônicas. Participaram deste ensaio clínico duplo-cego 16 voluntários com diferentes lesões do SNC, de ambos os sexos, idade média de 51,9±13,9 anos e marcha preservada. Os voluntários foram divididos aleatoriamente em 2 grupos (Treino FBM-T ativo + treino aeróbico e FBM-T placebo + treino aeróbico). O programa de reabilitação foi realizado em esteira ergométrica, na frequência de 2 vezes semanais e com duração total de 12 semanas. A FBM-T (3 lasers no λ= 660nm e 3 Lasers no λ= 808nm, 100mW, 6J/laser, 60seg/ponto, 36J por ponto, energia total 108J/cm2) foi aplicada em 3 pontos, sendo estes Fz, F7 e F8 segundo o Sistema Internacional 10-20 de EEG. Foram avaliados RMS do músculo reto femoral parético ou de maior comprometimento no pré-tratamento, 8ª semana e 12ª semana. Nota-se um aumento da atividade elétrica do grupo Laser nas coletas de RMS isotônica e isométrica, e redução do recrutamento muscular em ortostatismo quando comparados o início e o final do treinamento. Sugere-se que a FBM-T pode ter sido um fator influente para o aumento do recrutamento muscular no grupo Laser.