4,268 research outputs found

    Past and future blurring at fundamental length scale

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    We obtain the κ\kappa-deformed versions of the retarded and advanced Green functions and show that their causality properties are blurred in a time interval of the order of a length parameter q=1/(2κ)q=1/(2\kappa). The functions also indicate a smearing of the light cone. These results favor the interpretation of qq as a fundamental length scale below which the concept of a point in spacetime should be substituted by the concept of a fuzzy region of radius qq, as proposed long ago by Heisenberg.Comment: Essentially, this is the version published in the Phys. Rev. Lett. 105, 211601 (2010). It has 4 pages and contains 2 figure

    Novel IL2RG Mutation Causes Leaky TLOWB+NK+ SCID With Nodular Regenerative Hyperplasia and Normal IL-15 STAT5 Phosphorylation

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    X-linked severe combined immunodeficiency disease (SCID) is caused by mutations in the interleukin (IL)-2 receptor γ (IL2RG) gene and patients usually present with a TBNK SCID phenotype. Nevertheless, a minority of these patients present with a TBNK phenotype, similar to the IL-7R-deficient patients. We report a patient with a novel missense p.Glu297Gly mutation in the IL2RG gene presenting with a leaky TBNK SCID with delayed onset, moderate susceptibility to infections, and nodular regenerative hyperplasia. He presents with preserved STAT5 tyrosine phosphorylation in response to IL-15 stimulation but not in response to IL-2 and IL-7, resulting in the NK phenotype.info:eu-repo/semantics/publishedVersio

    Relativistic Green functions in a plane wave gravitational background

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    We consider a massive relativistic particle in the background of a gravitational plane wave. The corresponding Green functions for both spinless and spin 1/2 cases, previously computed by A. Barducci and R. Giachetti \cite{Barducci3}, are reobtained here by alternative methods, as for example, the Fock-Schwinger proper-time method and the algebraic method. In analogy to the electromagnetic case, we show that for a gravitational plane wave background a semiclassical approach is also sufficient to provide the exact result, though the lagrangian involved is far from being a quadratic one.Comment: Last paper by Professor Arvind Narayan Vaidya, 18 pages, no figure

    Lagrangian formulation for noncommutative nonlinear systems

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    In this work we use the well known formalism developed by Faddeev and Jackiw to introduce noncommutativity within two nonlinear systems, the SU(2) Skyrme and O(3) nonlinear sigma models. The final result is the Lagrangian formulations for the noncommutative versions of both models. The possibility of obtaining different noncommutative versions for these nonlinear systems is demonstrated.Comment: 8 pages. Revex 4.
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