10,705 research outputs found

    Outage-based ergodic link adaptation for fading channels with delayed CSIT

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    Link adaptation in which the transmission data rate is dynamically adjusted according to channel variation is often used to deal with time-varying nature of wireless channel. When channel state information at the transmitter (CSIT) is delayed by more than channel coherence time due to feedback delay, however, the effect of link adaptation can possibly be taken away if this delay is not taken into account. One way to deal with such delay is to predict current channel quality given available observation, but this would inevitably result in prediction error. In this paper, an algorithm with different view point is proposed. By using conditional cdf of current channel given observation, outage probability can be computed for each value of transmission rate RR. By assuming that the transmission block error rate (BLER) is dominated by outage probability, the expected throughput can also be computed, and RR can be determined to maximize it. The proposed scheme is designed to be optimal if channel has ergodicity, and it is shown to considerably outperform conventional schemes in certain Rayleigh fading channel model

    Side-View Operando Optical Microscopy Analysis of a Graphite Anode to Study Its Kinetic Hysteresis

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    Operando analyses have provided several breakthroughs in the construction of high-performance materials and devices, including energy storage systems. However, despite the advances in electrode engineering, the formidable issues of lithium intercalation and deintercalation kinetics cannot be investigated by using planar observations. This study concerns side-view operando observation by optical microscopy of a graphite anode based on its color changes during electrochemical lithiation. Since the graphite color varies according to the optical energy gap during lithiation and delithiation, this technique can be used to study the corresponding charge-discharge kinetics. In addition, the cell configuration uses liquid electrolytes similar to commercial cells, allowing practical application. Furthermore, this side-view observation has shown that microscale spatial variations in rate and composition control the insertion and deinsertion, revealing the kinetics throughout the whole electrode. The results of this study could enhance the fundamental understanding of the kinetics of battery materials

    Forbidden Channels and SIMP Dark Matter

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    In this review, we focus on dark matter production from thermal freeze-out with forbidden channels and SIMP processes. We show that forbidden channels can be dominant to produce dark matter depending on the dark photon and / or dark Higgs mass compared to SIMP.Comment: 5 pages, Prepared for the proceedings of the 13th International Conference on Gravitation, 3-7 July 201

    On thermal production of self-interacting dark matter

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    We consider thermal production mechanisms of self-interacting dark matter in models with gauged Z3Z_3 symmetry. A complex scalar dark matter is stabilized by the Z3Z_3, that is the remnant of a local dark U(1)dU(1)_d. Light dark matter with large self-interaction can be produced from thermal freeze-out in the presence of SM-annihilation, SIMP and/or forbidden channels. We show that dark photon and/or dark Higgs should be relatively light for unitarity and then assist the thermal freeze-out. We identify the constraints on the parameter space of dark matter self-interaction and mass in cases that one or some of the channels are important in determining the relic density.Comment: 26 pages, 11 figures, Version to appear in Journal of High Energy Physic

    Anti-neuroinflammatory Effects of Ethanol Extract of Inula helenium L (Compositae)

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    Purpose: To evaluate the in vitro antioxidant and anti- neuroinflammatory activities of Inula helenium extract (IHE) against lipopolysaccharide (LPS)-induced production of nitric oxide (NO) by primary microglial cells.Methods: Cell viability was estimated by 3-(4, 5-dimethylthiazol-2- yl)-2, 5- diphenyl-tetrazolium bromide (MTT) assay. Antioxidant activity was evaluated using 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assay. LPS-stimulated BV-2 microglia were used to study the expression and production of inflammatory mediators, including NO, inducible NO synthase (iNOS)and Interukin-6 (IL-6).Results: Pretreatment with IHE prior to LPS treatment significantly inhibited excessive production of NO (p < 0.001 at 20, 40, 80 and 100 μg/mL) in a dose-dependent manner, and was associated with downregulation of expression of inducible nitric oxide synthase (iNOS). IHE also suppressed the LPSinduced increase in IL-6 level (p < 0.01 at 40 and 80 μg/mL) in BV-2 cells. The antioxidant activity exhibited by IHE might play a critical role in ameliorating neuroinflammatory processes in LPSstimulated BV-2 microglial cells.Conclusion: IHE may be beneficial in preventing and treating neurodegenerative and oxidative stressrelated diseases.Keywords: Inula helenium, DPPH, Neurodegenerative diseases, Anti inflammatory, Anti-oxidant, Microglial cel
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