1,762 research outputs found

    An optimized power allocation algorithm for cognitive radio NOMA communication

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    The primary objective of cognitive radio network is to effectively utilize the unused spectrum bands. In cognitive radio networks, spectrum sharing between primary and secondary users is accomplished using either underlay or interweave cognitive radio approach. Non orthogonal multiple access (NOMA) is the proven technology in the present wireless developments, which allows the coexistence of multiple users in the same orthogonal block. The new paradigm cognitive radio NOMA (CR-NOMA) is one of the potential solutions to fulfill the demands of future wireless communication. This paper emphasizes on practical implementation of NOMA in cognitive radio networks to enhance the spectral efficiency. The goal is to increase the throughput of the secondary users satisfying the quality of service (QOS) requirements of primary users. To achieve this, we have presented the optimized power allocation strategy for underlay downlink scenario to support the simultaneous transmission of primary and secondary users. Furthermore, we have proposed QOS based power allocation scheme for CR-NOMA interweave model to support the coexistence of multiple secondary networks. Also, the changes adopted in implementing superposition coding (SC) and successive interference cancellation (SIC) for CR-NOMA are highlighted. Finally, simulation results validate the mathematical expressions that are derived for power allocation coefficient and outage probability

    The p66\u3csup\u3eShc\u3c/sup\u3e adaptor protein controls oxidative stress response in early bovine embryos

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    The in vitro production of mammalian embryos suffers from high frequencies of developmental failure due to excessive levels of permanent embryo arrest and apoptosis caused by oxidative stress. The p66Shc stress adaptor protein controls oxidative stress response of somatic cells by regulating intracellular ROS levels through multiple pathways, including mitochondrial ROS generation and the repression of antioxidant gene expression. We have previously demonstrated a strong relationship with elevated p66Shc levels, reduced antioxidant levels and greater intracellular ROS generation with the high incidence of permanent cell cycle arrest of 2-4 cell embryos cultured under high oxygen tensions or after oxidant treatment. The main objective of this study was to establish a functional role for p66Shc in regulating the oxidative stress response during early embryo development. Using RNA interference in bovine zygotes we show that p66Shc knockdown embryos exhibited increased MnSOD levels, reduced intracellular ROS and DNA damage that resulted in a greater propensity for development to the blastocyst stage. P66Shc knockdown embryos were stress resistant exhibiting significantly reduced intracellular ROS levels, DNA damage, permanent 2-4 cell embryo arrest and diminished apoptosis frequencies after oxidant treatment. The results of this study demonstrate that p66Shc controls the oxidative stress response in early mammalian embryos. Small molecule inhibition of p66Shc may be a viable clinical therapy to increase the developmental potential of in vitro produced mammalian embryos. © 2014 Betts et al

    Additive Nonparametric Reconstruction of Dynamical Systems from Time Series

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    We present a nonparametric way to retrieve a system of differential equations in embedding space from a single time series. These equations can be treated with dynamical systems theory and allow for long term predictions. We demonstrate the potential of our approach for a modified chaotic Chua oscillator.Comment: accepted for Phys. Rev. E, Rapid Com

    Laser-Induced Skyrmion Writing and Erasing in an Ultrafast Cryo-Lorentz Transmission Electron Microscopy

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    We demonstrate that light-induced heat pulses of different duration and energy can write skyrmions in a broad range of temperatures and magnetic field in FeGe. Using a combination of camera-rate and pump-probe cryo-Lorentz Transmission Electron Microscopy, we directly resolve the spatio-temporal evolution of the magnetization ensuing optical excitation. The skyrmion lattice was found to maintain its structural properties during the laser-induced demagnetization, and its recovery to the initial state happened in the sub-{\mu}s to {\mu}s range, depending on the cooling rate of the system

    Shape Deformation driven Structural Transitions in Quantum Hall Skyrmions

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    The Quantum Hall ground state away from ν=1\nu = 1 can be described by a collection of interacting skyrmions. We show within the context of a nonlinear sigma model, that the classical ground state away from ν=1\nu = 1 is a skyrmion crystal with a generalized N\'eel order. We show that as a function of filling ν\nu, the skyrmion crystal undergoes a triangle to square to triangle transition at zero temperature. We argue that this structural transition, driven by a change in the shape of the individual skyrmions, is stable to thermal and quantum fluctuations and may be probed experimentally.Comment: 4 pages (REVTEX) and 4 .eps figure

    A prospective randomised open labelled comparative study of anti inflammatory effects of topical 5% benzoyl peroxide gel vs topical 4% nicotinamide gel for grade I-II acne in a tertiary care hospital

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    Background: Acne vulgaris is a dermatological disorder characterised by formation of comedones and inflammatory lesions. The treatment of acne basically involves reduction of lesions. Benzoyl peroxide, in concentrations of 5%, 10%, and 20%, has been used effectively in the treatment of acne for more than 20 years. Nicotinamide/ Niacinamide is a newly-approved anti-acne drug with a potent anti-inflammatory effect. The present study assessed the efficacy of 5% Benzoyl peroxide gel in comparison to 4% Nicotinamide gel for topical treatment of mild to moderate acne vulgaris.Methods: In this study, the patients with mild to moderate acne vulgaris with inflammation were divided into two groups, group I was treated with topical 5% Benzoyl peroxide gel whereas topical Nicotinamide gel was given to the group II. Assessment of efficacy was done by total lesion counting according acne global severity index, the results were compared at the end of 2 weeks and 4 weeks with the baseline values.Results: At the end of this study, it was found that the reduction of inflammatory and total percentage of decrease in counts of lesions from baseline were highly significant in both the groups (p<0.001), between the groups, differences were statistically significant (p<0.001), therefore 5% Benzoyl peroxide gel has better efficacy than 4% Nicotinamide gel.Conclusions: Benzoyl peroxide is more efficacious than 4 % Nicotinamide gel in mild to moderate acne

    Functional outcome following conservative management of acetabular fractures

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    Background: Acetabular fractures are complex injuries caused due to high velocity injury and constitutes about 18 % of Pelvic fractures. To obtain articular congruency and anatomical reduction is the gold standard in treating these fractures. In this study we have studied about the functional outcome in acetabular fractures managed conservatively with the long-term follow.Methods: A retrospective study with prospective analysis done between 2011-2020 involved 39 patients with acetabular fractures who were treated conservatively at St John’s Medical college Hospital. Patients were followed up at 6 months, 1 year, 2 years and at the end of 5 years for functional evaluation and assessment with the clinical outcome scores with Merle d’Aubigne and Postel score &amp; Harris Hip Score.Results: Study included 39 patients with the average age of 41.3 years with 31 male and 8 female patients. Functional outcome score showed good to excellent results in 80%, fair to satisfactory results in 18%, 0.5 to 2% had poor result in the patient analyzed with both Merle d’Aubigne and Postel score and Harris Hip Score. 80 % of the patients were able to sit cross legged, 90% had returned to regular work and 10% of the patients changed their occupation to desk jobs.Conclusions: Conservative management of acetabular fractures gives a good long-term result following congruent reduction of the fracture, good early rehabilitation and gradual weight bearing. Return to activity of daily living was good even in congruently reduced acetabular dome fractures with good to excellent functional outcome scores

    Connected Network of Minima as a Model Glass: Long Time Dynamics

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    A simple model to investigate the long time dynamics of glass-formers is presented and applied to study a Lennard-Jones system in supercooled and glassy phases. According to our model, the point representing the system in the configurational phase space performs harmonic vibrations around (and activated jumps between) minima pertaining to a connected network. Exploiting the model, in agreement with the experimental results, we find evidence for: i) stretched relaxational dynamics; ii) a strong T-dependence of the stretching parameter; iii) breakdown of the Stokes-Einstein law.Comment: 4 pages (Latex), 4 eps figure

    Simulation of High Conversion Efficiency and Open-circuit Voltages Of {\alpha}-si/poly-silicon Solar Cell

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    The P+ {\alpha}-Si /N+ polycrystalline solar cell is molded using the AMPS-1D device simulator to explore the new high efficiency thin film poly-silicon solar cell. In order to analyze the characteristics of this device and the thickness of N+ poly-silicon, we consider the impurity concentration in the N+ poly-silicon layer and the work function of transparent conductive oxide (TCO) in front contact in the calculation. The thickness of N+ poly-silicon has little impact on the device when the thickness varies from 20 {\mu}m to 300 {\mu}m. The effects of impurity concentration in polycrystalline are analyzed. The conclusion is drawn that the open-circuit voltage (Voc) of P+ {\alpha}-Si /N+ polycrystalline solar cell is very high, reaching 752 mV, and the conversion efficiency reaches 9.44%. Therefore, based on the above optimum parameters the study on the device formed by P+ {\alpha}-Si/N+ poly-silicon is significant in exploring the high efficiency poly-silicon solar cell.Comment: 8 pages 6figures, 1 table

    Event-by-Event Search for Charged Neutral Fluctuations in Pb - Pb Collisions at 158-A-GeV

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    Results from the analysis of data obtained from the WA98 experiment at the CERN SPS have been presented. Some events have been filtered which show photon excess in limited η−ϕ\eta-\phi zones within the overlap region of the charged particle and photon multiplicity detectors.Comment: 6 pages, 4 figure
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