261 research outputs found

    Bounds On Anomalous Magnetic And Electric Moments Of Tau Lepton From LEP And Lepton Flavor Violation

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    The most stringent bounds on the anomalous magnetic and electric dipole moments of the tau lepton was derived by Escribano and Mass\'{o}[6] from the Z width at LEP in an effective lagrangian approach to the new physics. In this paper we point out that the higher dimensional operators introduced by Escribano and Mass\'{o} not only modify the neutral currents of the tau lepton to Z gauge boson and the photon, but also induce lepton flavor violation (LFV). The size of the LFV effect depends crucially on the dynamics of the lepton mass generation. Assuming the lepton mass matrices in the form of an Fritzsch ansatz, we point out that the experimental limit on μeγ\mu \to e \gamma will push the anomalous magnetic and electric dipole moments of the tau lepton down to 101110^{-11} and 1025ecm10^{-25} e cm respectively.Comment: 6 pages, latex, no figure

    Harnessing LSTM for Nonlinear Ship Deck Motion Prediction in UAV Autonomous Landing amidst High Sea States

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    Autonomous landing of UAVs in high sea states requires the UAV to land exclusively during the ship deck's "rest period," coinciding with minimal movement. Given this scenario, determining the ship's "rest period" based on its movement patterns becomes a fundamental prerequisite for addressing this challenge. This study employs the Long Short-Term Memory (LSTM) neural network to predict the ship's motion across three dimensions: longi-tudinal, transverse, and vertical waves. In the absence of actual ship data under high sea states, this paper employs a composite sine wave model to simulate ship deck motion. Through this approach, a highly accurate model is established, exhibiting promising outcomes within various stochastic sine wave combination models.Comment: 11 pages, 7 figures, accept by ICANDVC202

    The PWM strategies of grid-connected distributed generation active NPC inverters

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    The Neutral Point Clamped topology due to high efficiency, low leakage current and EMI, its integration is widely used in the distributed generation (DG) systems. However the main disadvantage of the NPC inverter is given by an unequal distribution of the losses in the semiconductor devices, which leads to an unequal distribution of temperature. By using the Active NPC topology, the power losses distribution problem is alleviated. The modulation strategy is a key issue for losses distribution in this topology. In this paper two known strategies are discussed and a new proposed PWM strategy, namely the Adjustable Losses Distribution (ALD) PWM strategy is proposed for better losses distribution in the Active NPC (ANPC) topology. Simulations using Simulink and the PLECS toolbox have been done for evaluating efficiency of different NPC topologies and some experimental results are presented in this paper to validate the operation of the different strategies.Peer ReviewedPostprint (published version

    Adiabatic Gravitational Perturbation During Reheating

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    We study the possibilities of parametric amplification of the gravitational perturbation during reheating in single-field inflation models. Our result shows that there is no additional growth of the super-horizon modes beyond the usual predictions.Comment: Refs added; New version to appear in PR

    Aqueous Extract of Black Maca (Lepidium meyenii) on Memory Impairment Induced by Ovariectomy in Mice

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    The present study aims to test two different doses of aqueous extract of black maca on learning and memory in ovariectomized (OVX) mice and their relation with malonalehyde (MDA), acetylcholinesterase (Ache) and monoamine oxidase (MAO) brain levels. Female mice were divided into five groups: (i) naive (control), (ii) sham, (iii) OVX mice and OVX mice treated with (iv) 0.50 g kg−1 and (v) 2.00 g kg−1 black maca. Mice were orally treated with distilled water or black maca during 35 days starting 7 days after surgery. Memory and learning were assessed using the water Morris maze (from day 23–27) and the step-down avoidance test (days 34 and 35). At the end of each treatment, mice were sacrificed by decapitation and brains were dissected out for MDA, Ache and MAO determinations. Black maca (0.5 and 2.0 g/kg) increased step-down latency when compared to OVX control mice. Black maca decreased MDA and Ache levels in OVX mice; whereas, no differences were observed in MAO levels. Finally, black maca improved experimental memory impairment induced by ovariectomy, due in part, by its antioxidant and Ache inhibitory activities

    Stat3 regulates microtubules by antagonizing the depolymerization activity of stathmin

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    Stat3 is a member of the signal transducer and activator of transcription family, which is important in cytokine signaling. Gene ablation studies have revealed a requirement for Stat3 in diverse biological processes (Akira, S. 2000. Oncogene. 19: 2607–2611; Levy, D.E., and C.K. Lee. 2002. J. Clin. Invest. 109:1143–1148). Previously, the function of Stat3 had been attributed exclusively to its transcriptional activity in the nucleus. In this study, we reveal an interaction between Stat3 and the microtubule (MT)-destabilizing protein stathmin. Stathmin did not overtly affect ligand-stimulated Stat3 activation. In contrast, the expression of Stat3 is required for the stabilization of MTs and cell migration. We further demonstrate that Stat3-containing cells are resistant to the MT-destabilizing effect of stathmin overexpression. In addition, down-regulation of stathmin protein levels in Stat3-deficient cells partially reversed the MT and migration deficiencies. Recombinant Stat3 was also capable of reversing stathmin inhibition of tubulin polymerization in vitro. Our results indicate that Stat3 modulates the MT network by binding to the COOH-terminal tubulin-interacting domain of stathmin and antagonizing its MT destabilization activity
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