Comparison of Linear and Nonlinear Equalization for Ultra-High Capacity Spectral Superchannels

In ultra-high-speed (>400Gb/s per wavelength), high-spectral efficiency coherent optical communication systems using multi-carrier spectral superchannels, the maximum reach is severely limited due to linear and, foremost, nonlinear impairments. Hence, the implementation of advanced digital signal processing (DSP) techniques in optical transceivers is crucial for alleviating the impact of such impairments. However, the DSP performance improvement comes at the expense of increased cost and power consumption. Given that the computational complexity of the applied linear and nonlinear equalizers is the factor that determines the trade-off between the performance improvement and cost, in this study we provide an extended analysis on the computational complexity of various linear and nonlinear equalization approaches. First, we draw a complexity comparison between a conventional OFDM coherent receiver versus a filter-bank based OFDM receiver and it is shown that the latter provides significant complexity savings. Second, we present a comparison between the digital back-propagation split-step Fourier (DBP-SSF) method and the inverse Volterra series transfer function nonlinear equalizer (IVSTF-NLE) in terms of performance and computational complexity for a 32 Gbaud polarization multiplexed (PM)-16 quadrature amplitude modulation (QAM) OFDM superchannel

Sarcome uterin a propos d’un cas et revue de la littérature

Les sarcomes utérins sont des tumeurs rares qui se révèlent le plus souvent par des métrorragies ou des douleurs pelviennes caractérisées par une diversité histopathologique et clinique importante et un pronostic médiocre. Nous avons analysé les difficultés diagnostiques, pronostiques et thérapeutiques posés par ces tumeurs en insistant sur la nécessité d’un diagnostic précoce

Simplified DSP-Based Signal-Signal Beat Interference Mitigation Technique for Direct Detection OFDM

Short- and medium-haul links in interdata center, access, and metro networks require cost-effective direct-detection wavelength-division multiplexing transceivers offering energy efficiency, high information spectral density (ISD), and dispersion tolerance. Single-sideband orthogonal frequency-division multiplexing (SSB-OFDM) with direct detection is a potential solution; however, it suffers a penalty from signal-signal beat interference (SSBI) caused by the square-law photodetection. In this paper, a novel DSP-based SSBI mitigation technique, with lower complexity than previously proposed methods, is proposed and assessed through numerical simulations for the first time. The performance improvement is quantified by simulations of 9 × 112 Gb/s 16-QAM SSB-OFDM signal with a net optical ISD of 2.1 (b/s)/Hz. The performance is shown to be similar to that of the more complex receiver-based iterative SSBI compensation technique. Simulations predict an 8.7 dB reduction in the required OSNR at the 7% overhead HD-FEC threshold, and increases up to 100% in maximum reach over uncompensated standard single-mode fibre using the proposed simplified SSBI compensation technique

Temporally stable coherent states for infinite well and P\"oschl-Teller potentials

This paper is a direct illustration of a construction of coherent states which has been recently proposed by two of us (JPG and JK). We have chosen the example of a particle trapped in an infinite square-well and also in P\"oschl-Teller potentials of the trigonometric type. In the construction of the corresponding coherent states, we take advantage of the simplicity of the solutions, which ultimately stems from the fact they share a common SU(1,1) symmetry \`a la Barut--Girardello. Many properties of these states are then studied, both from mathematical and from physical points of view.Comment: 48 pages, 21 figure

Generation and transmission of 85.4 Gb/s realtime 16QAM coherent optical OFDM signals over 400 km SSMF with preamble-less reception

This paper presents a real-time, coherent optical OFDM transmitter based on a field programmable gate array implementation. The transmitter uses 16QAM mapping and runs at 28 GSa/s achieving a data rate of 85.4 Gb/s on a single polarization. A cyclic prefix of 25% of the symbol duration is added enabling dispersion-tolerant transmission over up to 400 km of SSMF. This is the first transmission experiment performed with a real-time OFDM transmitter running at data rates higher than 40 Gb/s. A key aspect of the paper is the introduction of a novel method for OFDM symbol synchronization without relying on training symbols. Unlike conventional preamble-based synchronization methods which perform cross-correlations at regular time intervals and let the system run freely in between, the proposed method performs synchronization in a continuous manner ensuring correct symbol alignment at all times

Simplified DSP-Based Signal-Signal Beat Interference Mitigation for Direct-Detection Subcarrier Modulation

We proposed a novel SSBI mitigation technique with significantly lower DSP complexity. It was experimentally tested in 7×25 Gb/s WDM DD SSB 16-QAM N-SCM signal transmission over 480 km SSMF with a net ISD of 2.4 (b/s)/Hz

Peculiar Size Effects in Nanoscaled Systems

In this minireview, we intend to shed light on relatively recent examples related to the size and shape effects on materials at the nanoscale and their usage to test a set of quantum mechanics governed phenomena

Wheelchair service provision education for healthcare professional students, healthcare personnel and educators across low- to high-resourced settings: a scoping review

Purpose This review aimed to collate and summarize available research literature about wheelchair service provision education available to healthcare professional students, healthcare personnel and educators across low- to high-resourced settings. Methods The Joanna Briggs Institute methodological steps for scoping reviews were followed. Included studies were mainly sourced from Medline, Embase, CINAHL, Scopus, Academic Search Complete and ProQuest. Independent title, abstract and full-text screening with defined inclusion and exclusion criteria was performed. All screening and extraction were performed independently by two authors. A thematic approach was used to synthesize results. Data extracted from included studies were charted according to a template that we created. The study quality was also appraised. Results A total of 25 articles were included (11, 36% from high-income settings) with 12 (48%) observational studies and 13 (52%) experimental studies. The literature addressed three main topics: (1) assessing wheelchair service provision knowledge, (2) implementing training interventions using in-person, online and/or hybrid learning approaches and (3) describing current wheelchair service provision education globally. The most frequently reported training programs used were the Wheelchair Skills Program and the World Health Organization Wheelchair Service Training Package – Basic Level. Conclusion Limited information has been published about the integration of wheelchair content into the curricula of professional rehabilitation programs. Efforts to build international partnerships, improve the quality and currency of training programs and build resources that can assist educators in the integration of wheelchair-related content into professional rehabilitation programs should be prioritized. Implications for Rehabilitation This is the first review that examined and synthesized the current state of wheelchair service provision education for rehabilitation students and personnel across low- to high-income countries. Findings from this review indicate that there is limited information about the integration of wheelchair-related content into professional rehabilitation programs. Efforts to build international partnerships, standardize wheelchair service provision content and evaluation and integrate training into professional rehabilitation programs worldwide should be prioritized

Genomic Characterization of the Taylorella Genus

The Taylorella genus comprises two species: Taylorella equigenitalis, which causes contagious equine metritis, and Taylorella asinigenitalis, a closely-related species mainly found in donkeys. We herein report on the first genome sequence of T. asinigenitalis, analyzing and comparing it with the recently-sequenced T. equigenitalis genome. The T. asinigenitalis genome contains a single circular chromosome of 1,638,559 bp with a 38.3% GC content and 1,534 coding sequences (CDS). While 212 CDSs were T. asinigenitalis-specific, 1,322 had orthologs in T. equigenitalis. Two hundred and thirty-four T. equigenitalis CDSs had no orthologs in T. asinigenitalis. Analysis of the basic nutrition metabolism of both Taylorella species showed that malate, glutamate and alpha-ketoglutarate may be their main carbon and energy sources. For both species, we identified four different secretion systems and several proteins potentially involved in binding and colonization of host cells, suggesting a strong potential for interaction with their host. T. equigenitalis seems better-equipped than T. asinigenitalis in terms of virulence since we identified numerous proteins potentially involved in pathogenicity, including hemagluttinin-related proteins, a type IV secretion system, TonB-dependent lactoferrin and transferrin receptors, and YadA and Hep_Hag domains containing proteins. This is the first molecular characterization of Taylorella genus members, and the first molecular identification of factors potentially involved in T. asinigenitalis and T. equigenitalis pathogenicity and host colonization. This study facilitates a genetic understanding of growth phenotypes, animal host preference and pathogenic capacity, paving the way for future functional investigations into this largely unknown genus