63 research outputs found

    The Noncommutative Doplicher-Fredenhagen-Roberts-Amorim Space

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    This work is an effort in order to compose a pedestrian review of the recently elaborated Doplicher, Fredenhagen, Roberts and Amorim (DFRA) noncommutative (NC) space which is a minimal extension of the DFR space. In this DRFA space, the object of noncommutativity (θμν\theta^{\mu\nu}) is a variable of the NC system and has a canonical conjugate momentum. The DFRA formalism is constructed in an extended space-time with independent degrees of freedom associated with the object of noncommutativity θμν\theta^{\mu\nu}. A consistent algebra involving the enlarged set of canonical operators is described, which permits one to construct theories that are dynamically invariant under the action of the rotation group. A consistent classical mechanics formulation is analyzed in such a way that, under quantization, it furnishes a NC quantum theory with interesting results. The Dirac formalism for constrained Hamiltonian systems is considered and the object of noncommutativity θij\theta^{ij} plays a fundamental role as an independent quantity. It is also explained about the generalized Dirac equation issue, that the fermionic field depends not only on the ordinary coordinates but on θμν\theta^{\mu\nu} as well. The dynamical symmetry content of such fermionic theory is discussed, and we show that its action is invariant under P{\cal P}'. In the last part of this work we analyze the complex scalar fields using this new framework. As said above, in a first quantized formalism, θμν\theta^{\mu\nu} and its canonical momentum πμν\pi_{\mu\nu} are seen as operators living in some Hilbert space. In a second quantized formalism perspective, we show an explicit form for the extended Poincar\'e generators and the same algebra is generated via generalized Heisenberg relations. We also consider a source term and construct the general solution for the complex scalar fields using the Green function technique

    Análise de fluxos metabólicos com substrato isotopicamente marcado (13C-MFA) em S. typhimurium

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    Linhagens atenuadas de Salmonella têm sido estudadas para produção e veiculação de substâncias com fins terapêuticos. Modelos metabólicos à escala genômica são ferramentas importantes no desenvolvimento de estratégias de engenharia metabólica. Este trabalho teve por objetivo obter dados experimentais para aprimorar o modelo metabólico e aprofundar o conhecimento do metabolismo de S. typhimurium (St). Foram realizados cultivos contínuos à taxa de diluição (D) de 0,24 e 0,48 h-1, utilizando U-13C-glicose como substrato. Aminoácidos da biomassa foram analisados por GC-MS. A análise de fluxos metabólicos permitiu determinar a distribuição de fluxos nas principais vias metabólicas de St. A glicólise foi a via majoritamente utilizada para catabolisar a glicose. As maiores diferenças nos fluxos estimados, para as duas D, verificaram-se nas vias anapleróticas. Sobrepondo os dados de fluxos intracelulares ao modelo metabólico será gerado um modelo mais preciso do metabolismo de S. typhimurium
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