On some classes of exactly-solvable Klein-Gordon equations

In this work we discuss some exactly solvable Klein-Gordon equations. We basically discuss the existence of classes of potentials with different nonrelativistic limits, but which shares the intermediate effective Schroedinger differential equation. We comment about the possible use of relativistic exact solutions as approximations for nonrelativistic inexact potentials. (c) 2005 Elsevier B.V. All rights reserved.

Equivalence of the Duffin-Kemmer-Petiau and Klein-Gordon-Fock equations

A strict proof of the equivalence of the Duffin-Kemmer-Petiau and Klein-Gordon Fock theories is presented for physical S-matrix elements in the case of charged scalar particles minimally interacting with an external or quantized electromagnetic field. The Hamiltonian canonical approach to the Duffin - Kemmer Petiau theory is first developed in both the component and the matrix form. The theory is then quantized through the construction of the generating functional for the Green's functions, and the physical matrix elements of the S-matrix are proved to be relativistic invariants. The equivalence of the two theories is then proved for the matrix elements of the scattered scalar particles using the reduction formulas of Lehmann, Symanzik, and Zimmermann and for the many-photon Green's functions.

Imigração e teorias antropólogicas no Brasil (1910-1920)

Brazil takes pride in its alleged lack of racial discrimination. These idealized racial relations are a construction of enlightened elites. This article analyzes one of the main cultural publications in the country in order to establish how European anthropological theories were interpreted by Brazilian intelectuals. In the reappraisal of the country proposed in the journal, the ethnic question was intensely discussed. A whitening of the population was generally perceived as a sort of magic solution to the contradictions in a multiracial, heterogeneous and rigidly hierarchic society. This natural process might be accelerated by an inflow of European immigration. The many expectations and tensions surrounding immigration were expressed in the construction of categories of desirable and undesirable immigrants. Thereof an ideal white country emerged, far away from the myth of racial democracy, which has not materialized in Brazilian society today.

Absence of Klein's paradox for massive spinless bosons coupled by a nonminimal vector interaction

A few properties of the nonminimal vector interaction in the Duffin-Kemmer-Petiau theory in the scalar sector are revised. In particular, it is shown that the nonminimal vector interaction has been erroneously applied to the description of elastic meson-nucleus scatterings and that the space component of the nonminimal vector interaction plays a peremptory role for the confinement of bosons whereas its time component contributes to the leakage. Scattering in a square step potential is used to show that Klein's paradox does not manifest in the case of a nonminimal vector coupling. Copyright © owned by the author(s) under the terms of the Creative Commons Attribution- NonCommercial-ShareAlike Licence.

Coincidences of self-maps on Klein bottle fiber bundles over the circle

The main purpose of this work is to study coincidences of fiber-preserving self-maps over the circle S 1 for spaces which are fiberbundles over S 1 and the fiber is the Klein bottle K. We classify pairs of self-maps over S 1 which can be deformed fiberwise to a coincidence free pair of maps. © 2012 Pushpa Publishing House.

Las teorias de la poblacion de John Maynard Keynes y el concepto de optimo""

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Teorias y politicas de poblacion

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Planificacion de los asentamientos humanos en America Latina y el Caribe: teorias y metodologias; texto resumen

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Notas acerca de la familia y las teorias de la fecundidad

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Teorias de conta corrente: uma aplicação ao caso do Brasil nos anos noventa

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

O evolucionismo no ensino de Biologia: investigação das teorias de Lamarck e Darwin expostas nos livros didáticos de Biologia do Plano Nacional do Livro Didático do ensino médio - PNLEM

Pós-graduação em Educação - IBRC

Um contraste entre as teorias cognitivas da consciência de Baars e Dennett: o espaço de trabalho global seria um teatro cartesiano?

Pós-graduação em Filosofia - FFC

Teorias duais massivas de spin-2 em D=2+1 via ação mestra e imersão de Noether

Pós-graduação em Física - FEG

Operador quaterniônico de Klein-Gordon-Dirac

Pós-graduação em Matemática - IBILCE

Teorias raciais e interpretação histórica: o Instituto Histórico e Geográfico de São Paulo (1894-1940)

Pós-graduação em História - FCLAS