Feynman versus Bakamjian-Thomas in Light Front Dynamics

We compare the Bakamjian-Thomas (BT) formulation of relativistic few-body systems with light front field theories that maintain closer contact with Feynman diagrams. We find that Feynman diagrams distinguish Melosh rotations and other kinematical quantities belonging to various composite subsystem frames that correspond to different loop integrals. The BT formalism knows only the rest frame of the whole composite system, where everything is evaluated.Comment: 5 page

Ecological and epidemiological models are both useful for SARS-CoV-2

Non peer reviewe

Light-front quark distributions in the nucleon and nucleon electromagnetic form factors

Longitudinal and transverse quark momentum distributions in the nucleon are calculated from a phenomenological quark-nucleon vertex function obtained through an investigation of the nucleon electromagnetic form factors within a light-front framework.Comment: 6 pages, 11 figs. proceedings of LC2009, to appear in Nucl. Phys.

Three-Fermion Bound States on the Light Front

We investigate the stability of the relativistic three-fermion system with a zero-range force in the light front form. In particular, introducing an invariant cut-off, we study the dependence of the bound state on the coupling strength also for cases where the two-fermion system is unbound. The relativistic Thomas collapse is discussed by solving the fully coupled integral equation system. Furthermore, we explicitly investigate the ground state mass of the three-fermion system and compare to previous simplified calculations.Comment: 23 pages, 6 figure

Redescription of the fish-parasitic isopod Cymothoa ianuarii Schioedte & Meinert, 1884 and further records of C. excisa Perty, 1833 and C. oestrum (Linnaeus, 1758) (Isopoda: Cymothoida: Cymothoidae) from Brazil

Cymothoa ianuarii Schioedte & Meinert, 1884 is rediscovered almost 136 years after its original description and redescribed from specimens collected in the state of São Paulo. This species is mainly characterized by adult females with cephalon with conspicuous eyes and not deeply immersed in pereonite 1, pereonites 5-6 much wider than 4, pleotelson twice as wide as long and pleopods 1-5 decreasing in size; Cymothoa excisa Perty, 1833 and C. oestrum (Linnaeus, 1758) are recorded from the state of Bahia. Illustrations and an updated distribution map for these species in Brazil are provided

Three-boson relativistic bound states with zero-range interaction

For the zero-range interaction providing a given mass M_2 of the two-body bound state, the mass M_3 of the relativistic three-boson state is calculated. We have found that the three-body system exists only when M_2 is greater than a critical value M_c approximately 1.43 m (m is the constituent mass). For M_2=M_c the mass M_3 turns into zero and for M_2<M_c there is no solution with real value of M_3.Comment: 7 pages, 4 figure

The Research, development and innovation policy in Brazil and the prospects for the development of Industry 4.0 in the Manaus Free Trade Zone

The main objective of this article is to analyze the Brazilian public policy to promote research, development and innovation and the prospects for Industry 4.0 in the Industrial Pole of Manaus. For this, a documental and bibliographic survey was carried out with the objective of identifying public policies to encourage research, development and innovation in Brazil, as well as the initiatives of the Manaus Free Trade Zone for the development of Industry 4.0. Thus, the correlations between the public policies of the Brazilian government and its local perspectives in the Industrial Pole of Manaus were identified, highlighting that the main currently existing initiatives stem from the mandatory investment in RD&amp;I contained in Brazilian legislation and how important is the participation of the National State for the development of Industry 4.0 initiatives in the Manaus Free Trade Zone.&nbsp