Hermitian Dirac Hamiltonian in time dependent gravitational field

It is shown by a straightforward argument that the Hamiltonian generating the time evolution of the Dirac wave function in relativistic quantum mechanics is not hermitian with respect to the covariantly defined inner product whenever the background metric is time dependent. An alternative, hermitian, Hamiltonian is found and is shown to be directly related to the canonical field Hamiltonian used in quantum field theory.Comment: 9 pages, final version, to appear in Class. Quant. Gra

High-resolution Fourier-transform XUV photoabsorption spectroscopy of 14N15N

The first comprehensive high-resolution photoabsorption spectrum of 14N15N has been recorded using the Fourier-transform spectrometer attached to the Desirs beamline at the Soleil synchrotron. Observations are made in the extreme ultraviolet (XUV) and span 100,000-109,000 cm-1 (100-91.7 nm). The observed absorption lines have been assigned to 25 bands and reduced to a set of transition energies, f values, and linewidths. This analysis has verified the predictions of a theoretical model of N2 that simulates its photoabsorption and photodissociation cross section by solution of an isotopomer independent formulation of the coupled-channel Schroedinger equation. The mass dependence of predissociation linewidths and oscillator strengths is clearly evident and many local perturbations of transition energies, strengths, and widths within individual rotational series have been observed.Comment: 14 pages, 8 figures, one data archiv

Chitosan and poly(Methyl methacrylate-co-butyl methacrylate) bioclends: a compatibility study.

Made available in DSpace on 2015-04-15T05:43:44Z (GMT). No. of bitstreams: 1 souza2014.pdf: 1629099 bytes, checksum: 2211f33daee6bb1d462adff4937e5ac3 (MD5) Previous issue date: 2015-04-14201

The interplay of university and industry through the FP5 network

To improve the quality of life in a modern society it is essential to reduce the distance between basic research and applications, whose crucial roles in shaping today's society prompt us to seek their understanding. Existing studies on this subject, however, have neglected the network character of the interaction between university and industry. Here we use state-of-the-art network theory methods to analyze this interplay in the so-called Framework Programme--an initiative which sets out the priorities for the European Union's research and technological development. In particular we study in the 5th Framework Programme (FP5) the role played by companies and scientific institutions and how they contribute to enhance the relationship between research and industry. Our approach provides quantitative evidence that while firms are size hierarchically organized, universities and research organizations keep the network from falling into pieces, paving the way for an effective knowledge transfer.Comment: 21 pages (including Appendix), 8 figures. Published online at http://stacks.iop.org/1367-2630/9/18

The Campinas and Region Natural Agriculture Association-s Participatory Guarantee System: a case study in Brazil.

Abstract: The research aimed to review the context in which the Brazilian regulation of organic agriculture was conceived and to conduct a study of the first PGS (Participatory Guarantee System) registered in Brazil. Such PGS is part of the Campinas and Region Natural Agriculture, located in the state of San Paolo. The research sought to understand the farmers´ objectives and motivations for adopting the PGS and their experiences within this social control mechanism. The participants in this research identified as main advantages of the PGS: extended experience sharing, participatory decision-making and collective strategies for purchase and marketing. Those previously certified by third party systems unanimously declared that the PGS proved to be more stringent and reliable as an organic conformity assessment system. However, the farmers also highlighted that paperwork required by the government from PGSs has increased and that indirect costs continue to be the main challenges that they face

Scattering and self-adjoint extensions of the Aharonov-Bohm hamiltonian

We consider the hamiltonian operator associated with planar sec- tions of infinitely long cylindrical solenoids and with a homogeneous magnetic field in their interior. First, in the Sobolev space $\mathcal H^2$, we characterize all generalized boundary conditions on the solenoid bor- der compatible with quantum mechanics, i.e., the boundary conditions so that the corresponding hamiltonian operators are self-adjoint. Then we study and compare the scattering of the most usual boundary con- ditions, that is, Dirichlet, Neumann and Robin.Comment: 40 pages, 5 figure

Comportamento mandioca de mesa sob adubação, em área dependente de chuva, em Petrolina-PE.

Com objetivo de comparar comportamento das variedades de mandioca de mesa sob adubação, em área dependente de chuva, foi realizado o presente trabalho entre fevereiro de 2010 e novembro de 2011, nas comunidades Pereiros, Caiçara e Mudubim, pertencentes ao município de Petrolina/PE. A adubação constou de 2,0 t ha -1 de calcário dolomítico, em área total, e nos sulcos, 60 kg ha-1 de P22OO55, na forma de superfosfato simples, além da imersão das manivas cortadas numa solução de sulfato de zinco 2%. As variedades utilizadas foram Brasília e Gema de Ovo e o experimento foi realizado em delineamento inteiramente casualizado, com dois tratamentos e 4 repetições. Na ausência da adubação as variedades Brasília e Gema de Ovo não apresentaram diferenças significativas em produção de raízes e da planta inteira, porém na presença da calagem e fósforo a variedade Gema de Ovo supera a variedade Brasília em todos os aspectos de produtividade, seja da parte aérea, da raiz ou da planta inteira, apresentando respectivamente 18,7, 36,7 e 59,2 t.ha-1. A variedade Gema de Ovo destaca-se sobre as demais na produção de parte aérea nas comunidades dos Pereiros (19,85 t.ha-1) e Caiçara (13,87 t.ha-1), indicando ser uma variedade adequada, também para uso da parte aérea fenada na alimentação animal