420 research outputs found

    Photon deflection by a Coulomb field in noncommutative QED

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    In noncommutative QED photons present self-interactions in the form of triple and quartic interactions. The triple interaction implies that, even though the photon is electrically neutral, it will deflect when in the presence of an electromagnetic field. If detected, such deflection would be an undoubted signal of noncommutative space-time. In this work we derive the general expression for the deflection of a photon by any electromagnetic field. As an application we consider the case of the deflection of a photon by an external static Coulomb field.Comment: 07 pages, some typos corrected, accepted for publication in JP

    Noncommutative Space Corrections on the Klein-Gordon and Dirac Oscillators Spectra

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    We consider the influence of a noncommutative space on the Klein-Gordon and the Dirac oscillators. The nonrelativistic limit is taken and the θ\theta-modified Hamiltonians are determined. The corrections of these Hamiltonians on the energy levels are evaluated in first-order perturbation theory. It is observed a total lifting of the degeneracy to the considered levels. Such effects are similar to the Zeeman splitting in a commutative space.Comment: 15 pages, 2 figures, improvements and changes are added, Final version published in IJMP

    Biocontrol of cantaloupe damping-off disease caused by Fusarium semitectum by using formulations of antagonistic fungi

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    oai:ojs.ppmj.net:article/2Antagonistic capability of 19 isolates of fungi isolated from rizosphere of cantaloupe plants was tested in vitro against growth of Fusarium semitectum isolate the causal pathogen of damping- off of cantaloupe. Trichoderma viride (isolate no. 17), T. harzianum (isolate no. 19) and Fusarium concolar  (isolate no.4) showed  significant  percentage of inhibition  against  to  F. semitectum. The effect of carrier formulations of antagonistic fungi (talc based powder and rice bran) on damping-off of cantaloupe were tested under greenhouse and field conditions.  In greenhouse experiments, application of antagonistic fungi with rice bran formulation two weeks before planting caused the highest percentage of survival plants in pre and post damping-off (83.33 and 75%, respectively), whereas application of talc based powder formulation significantly increased percentage of plant survival at the time of planting in pre and post damping-off (91.67 and 75%, respectively). In field experiments, application of tested formulations of antagonistic fungi to infested soil with F. semitectum two weeks before planting resulted in higher percentage of plant survival in pre and post damping-off in both teste

    One-loop renormalization of general noncommutative Yang-Mills field model coupled to scalar and spinor fields

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    We study the theory of noncommutative U(N) Yang-Mills field interacting with scalar and spinor fields in the fundamental and the adjoint representations. We include in the action both the terms describing interaction between the gauge and the matter fields and the terms which describe interaction among the matter fields only. Some of these interaction terms have not been considered previously in the context of noncommutative field theory. We find all counterterms for the theory to be finite in the one-loop approximation. It is shown that these counterterms allow to absorb all the divergencies by renormalization of the fields and the coupling constants, so the theory turns out to be multiplicatively renormalizable. In case of 1PI gauge field functions the result may easily be generalized on an arbitrary number of the matter fields. To generalize the results for the other 1PI functions it is necessary for the matter coupling constants to be adapted in the proper way. In some simple cases this generalization for a part of these 1PI functions is considered.Comment: 1+26 pages, figures using axodraw, clarifications adde

    Comments on Non-Commutative Phenomenology

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    It is natural to ask whether non-commutative geometry plays a role in four dimensional physics. By performing explicit computations in various toy models, we show that quantum effects lead to violations of Lorentz invariance at the level of operators of dimension three or four. The resulting constraints are very stringent.Comment: Correction of an error in the U(1) and U(N) calculation leads to stronger limits than those given previously Clarifying comments and reference adde

    Positronium Hyperfine Splitting in Non-commutative Space at the Order α6\alpha^6

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    We obtain positronium Hyperfine Splitting owing to the non-commutativity of space and show that, in the leading order, it is proportional to θα6\theta \alpha^6 where, θ\theta is the parameter of non-commutativity. It is also shown that spatial non-commutativity splits the spacing between n=2n=2 triplet excited levels E(23S1)E(23P2)E(2^3S_1)\to E(2^3P_2) which provides an experimental test on the non-commutativity of space.Comment: 7 pages, 2 figures, to appear in Phys. Rev.

    Renormalizability of noncommutative SU(N) gauge theory

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    We analyze the renormalizability properties of pure gauge noncommutative SU(N) theory in the θ\theta-expanded approach. We find that the theory is one-loop renormalizable to first order in θ\theta.Comment: 11 pages, minor changes, accepted for publication in JHE

    The form factors existing in the b->s g^* decay and the possible CP violating effects in the noncommutative standard model

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    We study the form factors appearing in the inclusive decay b -> s g^*, in the framework of the noncommutative standard model. Here g^* denotes the virtual gluon. We get additional structures and the corresponding form factors in the noncommutative geometry. We analyse the dependencies of the form factors to the parameter p\Theta k where p (k) are the four momenta of incoming (outgoing) b quark (virtual gluon g^*, \Theta is a parameter which measures the noncommutativity of the geometry. We see that the form factors are weaklyComment: 8 pages, 7 figure

    Evaluation of the effects of ozone therapy in the treatment of intra-abdominal infection in rats

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    INTRODUCTION: The antibacterial effect of ozone (O3) has been described in the extant literature, but the role of O3 therapy in the treatment of certain types of infection remains controversial. OBJECTIVES: To evaluate the effect of intraperitoneal (i.p.) O3 application in a cecal ligation/puncture rat model on interleukins (IL-6, IL-10) and cytokine-induced neutrophil chemoattractant (CINC)-1 serum levels, acute lung injury and survival rates. METHODS: Four animal groups were used for the study: a) the SHAM group underwent laparotomy; b) the cecal ligation/puncture group underwent cecal ligation/puncture procedures; and c) the CLP+O2 and CLP+O3 groups underwent CLP+ corresponding gas mixture infusions (i.p.) throughout the observation period. IL-6, CINC-1 and IL-10 concentrations were determined by enzyme-linked immunosorbent assay (ELISA). Acute lung injury was evaluated with the Evans blue dye lung leakage method and by lung histology. P<0.05 was considered significant. RESULTS: CINC-1 was at the lowest level in the SHAM group and was lower for the CLP+O3 group vs. the CLP+O2 group and the cecal ligation/puncture group. IL-10 was lower for the SHAM group vs. the other three groups, which were similar compared to each other. IL-6 was lower for the SHAM group vs. all other groups, was lower for the CLP+O3 or CLP+O2 group vs. the cecal ligation/puncture group, and was similar for the CLP+O3 group vs. the CLP+O2 group. The lung histology score was lower for the SHAM group vs. the other groups. The Evans blue dye result was lower for the CLP+O3 group vs. the CLP+O2 group and the cecal ligation/puncture group but similar to that of the SHAM group. The survival rate for the CLP+O3 group was lower than for the SHAM group and similar to that for the other 2 groups (CLP and CLP+O2). CONCLUSION: Ozone therapy modulated the inflammatory response and acute lung injury in the cecal ligation/puncture infection model in rats, although there was no improvement on survival rates
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