6,135 research outputs found

    Experimental Demonstration of Dual Polarization Nonlinear Frequency Division Multiplexed Optical Transmission System

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    Multi-eigenvalues transmission with information encoded simultaneously in both orthogonal polarizations is experimentally demonstrated. Performance below the HD-FEC limit is demonstrated for 8-bits/symbol 1-GBd signals after transmission up to 207 km of SSMF

    Dual polarization nonlinear Fourier transform-based optical communication system

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    New services and applications are causing an exponential increase in internet traffic. In a few years, current fiber optic communication system infrastructure will not be able to meet this demand because fiber nonlinearity dramatically limits the information transmission rate. Eigenvalue communication could potentially overcome these limitations. It relies on a mathematical technique called "nonlinear Fourier transform (NFT)" to exploit the "hidden" linearity of the nonlinear Schr\"odinger equation as the master model for signal propagation in an optical fiber. We present here the theoretical tools describing the NFT for the Manakov system and report on experimental transmission results for dual polarization in fiber optic eigenvalue communications. A transmission of up to 373.5 km with bit error rate less than the hard-decision forward error correction threshold has been achieved. Our results demonstrate that dual-polarization NFT can work in practice and enable an increased spectral efficiency in NFT-based communication systems, which are currently based on single polarization channels

    Experimental Verification of Rate Flexibility and Probabilistic Shaping by 4D Signaling

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    The rate flexibility and probabilistic shaping gain of 44-dimensional signaling is experimentally tested for short-reach, unrepeated transmission. A rate granularity of 0.5 bits/QAM symbol is achieved with a distribution matcher based on a simple look-up table.Comment: Presented at OFC'18, San Diego, CA, US

    The Glitter of Carbon Nanostructures in Hybrid/Composite Hydrogels for Medicinal Use

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    In recent years, we have witnessed to fast developments in the medicinal field of hydrogels containing various forms of integrated nanostructured carbon that adds interesting mechanical, thermal, and electronic properties. Besides key advances in tissue engineering (especially for conductive tissue, such as for the brain and the heart), there has been innovation also in the area of drug delivery on-demand, with engineered hydrogels capable of repeated response to light, thermal, or electric stimuli. This mini-review focusses on the most promising developments as applied to the gelation of protein/ peptide (including self-assembling amino acids and low-molecular-weight gelators), polysaccharide, and/or synthetic polymer components in medicine. The emerging field of graphene-only hydrogels is also briefly discussed, to give the reader a full flavor of the rising new paradigms in medicine that are made possible through the integration of nanostructured carbon (e.g., carbon nanotubes, nanohorns, nanodiamonds, fullerene, etc.). Nanocarbons are offering great opportunities to bring on a revolution in therapy that the modern medicinal chemist needs to master, to realise their full potential into powerful therapeutic solutions for the patient

    Constellation Shaping for WDM systems using 256QAM/1024QAM with Probabilistic Optimization

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    In this paper, probabilistic shaping is numerically and experimentally investigated for increasing the transmission reach of wavelength division multiplexed (WDM) optical communication system employing quadrature amplitude modulation (QAM). An optimized probability mass function (PMF) of the QAM symbols is first found from a modified Blahut-Arimoto algorithm for the optical channel. A turbo coded bit interleaved coded modulation system is then applied, which relies on many-to-one labeling to achieve the desired PMF, thereby achieving shaping gain. Pilot symbols at rate at most 2% are used for synchronization and equalization, making it possible to receive input constellations as large as 1024QAM. The system is evaluated experimentally on a 10 GBaud, 5 channels WDM setup. The maximum system reach is increased w.r.t. standard 1024QAM by 20% at input data rate of 4.65 bits/symbol and up to 75% at 5.46 bits/symbol. It is shown that rate adaptation does not require changing of the modulation format. The performance of the proposed 1024QAM shaped system is validated on all 5 channels of the WDM signal for selected distances and rates. Finally, it was shown via EXIT charts and BER analysis that iterative demapping, while generally beneficial to the system, is not a requirement for achieving the shaping gain.Comment: 10 pages, 12 figures, Journal of Lightwave Technology, 201

    Saúde e sociedade na realidade do trabalho da equipe de saúde da família

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    O vídeo, apresenta o modelo biomédico e a determinação social da doença. Reflete sobre a influência das relações sociais na constituição dos modelos de saúde e sobre as diferentes formas de pensar o processo saúde-doença. Vídeo 1 do módulo 2 que compõe o Curso de Especialização em Saúde da Família.1.0Ministério da Saúdes/OPAS/OM

    Targeting interleukin-1β protects from aortic aneurysms induced by disrupted transforming growth factor β signaling

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    Aortic aneurysms are life-threatening conditions with effective treatments mainly limited to emergency surgery or trans-arterial endovascular stent grafts, thus calling for the identification of specific molecular targets. Genetic studies have highlighted controversial roles of transforming growth factor β (TGF-β) signaling in aneurysm development. Here, we report on aneurysms developing in adult mice after smooth muscle cell (SMC)-specific inactivation of Smad4, an intracellular transducer of TGF-β. The results revealed that Smad4 inhibition activated interleukin-1β (IL-1β) in SMCs. This danger signal later recruited innate immunity in the adventitia through chemokine (C-C motif) ligand 2 (CCL2) and modified the mechanical properties of the aortic wall, thus favoring vessel dilation. SMC-specific Smad4 deletion in Il1r1- or Ccr2-null mice resulted in milder aortic pathology. A chronic treatment with anti-IL-1β antibody effectively hampered aneurysm development. These findings identify a mechanistic target for controlling the progression of aneurysms with compromised TGF-β signaling, such as those driven by SMAD4 mutations
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