Digital Back Propagation via Sub-band Processing in Spatial Multiplexing Systems

An advanced digital backward-propagation (DBP) method using a separate-channels approach (SCA) is investigated for the compensation of inter-channel nonlinearities in spatial- and wavelength-multiplexed systems. Compared to the conventional DBP, intra- and inter-mode cross-phase modulation can be efficiently compensated by including the effect of the inter-channel walk-off in the nonlinear step of the split-step Fourier method. We found that the SCA-DBP relaxes the step size requirements by a factor of 10, while improving performance by 0.8 dB for large walk-off and strong linear coupling. For the first time, it is shown that in spatial multiplexed systems transmission performance can be improved by sub-band processing of back propagated channels

Experimental Demonstration of a Simplified SOA Nonlinearity Mitigation scheme

We experimentally demonstrated a digital learned-filter mitigation scheme for semiconductor optical amplifier-induced nonlinear distortion of single-polarisation 32 GBd 16QAM and 64QAM signals in a back-to-back configuration

Pilot-aided Pump Dithering Removal in Degenerate FWM-based Optical Phase Conjugation Systems with Higher-order QAM

A pump dithering removal algorithm, based on pilot sequence-aided DSP, is proposed and experimentally validated in dual polarization 64 QAM optical phase conjugation system. A 4.2 dB SNR improvement was observed due to the SBS suppression

Ensino Superior nos institutos federais: inserção flexibilizada e experiências com a diversificação dos cursos

Este texto apresenta um estudo sobre a inserção do ensino superior nos Institutos Federais de Educação, Ciência e Tecnologia (IF’s), enfatizando as experiências históricas dessas instituições com a oferta flexibilizada e diversificada de seus cursos. Para proceder à análise, o centenário dos IF’s, período que abrange os anos de 1909 a 2008, foi estruturado e dividido em dois períodos: atuação até o nível médio e atuação no nível superior. Foram selecionadas duas categorias de análise extraídas da leitura interpretativa da legislação educacional: ensino técnico-profissional e área tecnológica, por meio das quais se descreveu como essas categorias foram utilizadas para justificar a organização de cursos superiores em caráter diversificado dos habitualmente ofertados nas universidades. Também se analisou como estas categorias estabelecem as diferenças entre as instituições de ensino superior e os IF’s, e como caracterizam o processo de formação acadêmica dos jovens, como mero processo de formação técnico-profissional e tecnológica, subserviente às demandas de mercado

A CONCEPÇÃO DE TRABALHO NA EDUCAÇÃO BÁSICA: CAMINHOS PARA A FORMAÇÃO DA JUVENTUDE NO INSTITUTO FEDERAL DE EDUCAÇÃO, CIÊNCIA E TECNOLOGIA DO CEARÁ

ABSTRACT: In 2008 two laws that changed the didactic- pedagogic and administrative organization of vocational schools were enacted: the Law 11.741/2008, which incorporated the Technical Professional Education for the Middle Level to Basic Education; and Law 11.892/2008,which has transformed Agrotechnical Schools, the CEFET 's and some technical schools linked to universities into Colleges of Education, Science and Technology (IFs). These institutions have been operating at all levels and types of education provided in the Law of Directives and Bases of National Education number 9394/1996, with the exception of Early Childhood Education. Vocational and training schools, which gave origin to the IFs,have historically restricted youth education to teaching professional techniques, but due to the reformist laws, they were led to revise their conceptions of work and education. Thus, the goal of this article is to analyze the concepts of Basic Education and work that permeate these laws and the organization of educational work at IFCE. Have these laws been promoting a rupture with the history of vocational education in the country? Have the IFs been accomplishing a teaching job in addition to technical training? The choice for these questions was motivated by two main reasons: a) Vocational Education in the aforementioned institutions have traditionally been restricted to the qualification of the labor force for learning a technical profession, without relating it to issues that concern basic education; b) The Reform of Basic Education, from 1990 to 2013, was conducted in the context of capital's structural crisis and aimed to adapt the educational system to the demands of productive sectors. Thus, the main objective of this paper is to explain the contradictions that exist in project of formation of the working class, in the context of a conflictual society divided into classes, a situation that alienates the youth to live this time forever.RESUMO: No ano de 2008 foram promulgadas duas leis que alteraram a organização didático-pedagógica e administrativa das escolas profissionalizantes: a Lei no 11.741/2008, que incorporou a Educação Profissional Técnica de Nível Médio à Educação Básica; e a Lei no 11.892/2008, que transformou as Escolas Agrotécnicas, os CEFET’s e algumas Escolas Técnicas vinculadas às universidades em Institutos de Educação, Ciência e Tecnologia (IF’s). Estas instituições passaram a atuar em todos os níveis e modalidades de ensino previstos na Lei de Diretrizes e Bases da Educação n. 9394/1996, com exceção da Educação Infantil. As escolas profissionalizantes que originaram os IF’s, historicamente, restringiam a educação da juventude ao ensino de técnicas profissionais, mas por força das legislações reformistas foram conduzidas a rever suas concepções de trabalho e educação. Desse modo, o objeto de reflexão deste artigo são as concepções de Educação Básica e de trabalho que permeiam essas legislações e a organização do trabalho pedagógico no IFCE. Estariam estas leis promovendo uma ruptura com a história da educação profissional no país? Os IF’s estariam conseguindo realizar um trabalho pedagógico para além da formação técnica? A escolha destas questões foi motivada por duas razões centrais: a) a Educação Profissional nas instituições supracitadas, tradicionalmente se restringia à qualificação da força de trabalho para o aprendizado de uma profissão técnica, sem relacioná-la com assuntos referentes à Educação Básica; b) a reforma da Educação Básica, de 1990 a 2013, foi realizada no contexto da crise estrutural do capital e teve como objetivo adaptar o sistema educativo às demandas dos setores produtivos. Dessa forma, o principal objetivo deste texto é o de explicitar as contradições existentes em um projeto de formação da classe trabalhadora, no contexto de uma sociedade conflituosa e divida em classes, situação que aliena e hipoteca a juventude a viver o tempo presente eternamente

Frequency-modulated Chirp Signals for Single-photodiode Based Coherent LiDAR System

In this paper, we investigate two categories of linear frequency-modulated chirp signals suitable for single-photodiode based coherent light detection and ranging (LiDAR) systems, namely, the frequency-modulated continuous-wave (FMCW) single-sideband (SSB) signal and the amplitude-modulated double-sideband (DSB) signal, and compare their achievable receiver sensitivity performance. The DSB signal requires a simpler transmitter design, as it is real-valued and can be generated using a single-drive Mach-Zehnder modulator (MZM), while the SSB signal, which is frequency/phase modulated, requires an in-phase and quadrature modulator (IQM)-based transmitter. A theoretical analysis of direct-detection (DD) beating interference (BI) especially the local oscillator (LO) beating with itself, known as LO-LO BI, is presented. Both Monte Carlo simulations and experimental demonstrations are carried out. Good agreement between simulations and experiments is achieved. In comparison with the SSB system, the DSB signal-based system is affected by laser phase noise-induced power fluctuation, and also suffers a significant sensitivity penalty due to nonlinear LO-LO BI. A spectral guard band for mitigating LO-LO BI is necessary for the DSB signal, achieved at the expense of requiring a larger electrical bandwidth. In system tests with a delay line of 385 m, the SSB signal outperforms the DSB signal with a 10 dB better receiver sensitivity in the case with a guard band, and 25 dB better sensitivity without a guard band

Metformin-induced lactic acidosis: a case series

<p>Abstract</p> <p>Introduction</p> <p>Unlike other agents used in the treatment of type 2 diabetes mellitus, metformin has been shown to reduce mortality in obese patients. It is therefore being increasingly used in higher doses. The major concern of many physicians is a possible risk of lactic acidosis. The reported frequency of metformin related lactic acidosis is 0.05 per 1000 patient-years; some authors advocate that this rate is equal in those patients not taking metformin.</p> <p>Case presentation</p> <p>We present two case reports of metformin-associated lactic acidosis. The first case is a 77 year old female with a past medical history of hypertension and type 2 diabetes mellitus who had recently been prescribed metformin (3 g/day), perindopril and acetylsalicylic acid. She was admitted to the emergency department two weeks later with abdominal pain and psychomotor agitation. Physical examination revealed only signs of poor perfusion. Laboratory evaluation revealed hyperkalemia, elevated creatinine and blood urea nitrogen and mild leukocytosis. Arterial blood gases showed severe lactic acidemia. She was admitted to the intensive care unit. Vasopressor and ventilatory support was initiated and continuous venovenous hemodiafiltration was instituted. Twenty-four hours later, full clinical recovery was observed, with return to a normal serum lactate level. The patient was discharged from the intensive care unit on the sixth day. The second patient is a 69 year old male with a past medical history of hypertension, type 2 diabetes mellitus and ischemic heart disease who was on metformin (4 g/day), glycazide, acetylsalicylic acid and isosorbide dinitrate. He was admitted to the emergency department in shock with extreme bradycardia. Initial evaluation revealed severe lactic acidosis and elevated creatinine and urea. The patient was admitted to the Intensive Care Unit and commenced on continuous venovenous hemodiafiltration in addition to other supportive measures. A progressive recovery was observed and he was discharged from the intensive care unit on the seventh day.</p> <p>Conclusion</p> <p>We present two case reports of severe lactic acidosis most probably associated with high doses of metformin in patients with no known contraindications for metformin prescription. In both patients no other condition was identified to cause such severe lactic acidosis. Although controversial, lactic acidosis should be considered in patients taking metformin.</p

Riparian ecotones and spatial variation of fish assemblages in Portuguese lowland streams

The first results of a long-term study on the role of riparian ecotones on the population and community dynamics of Iberian stream fish are presented and discussed . Riparian and macrophyte cover, bank slope and depth were among the most important variables affecting fish distribution . In general small fish favoured shallow areas with high macrophyte cover, whereas large fish dominated in deep areas with a high riparian cover . Slight spatial changes in terrestrial prey use were found suggesting a minor role for this resource during autumn . Finally, no significant spatial differences were found for linear growth, although some differences were obtained for the condition facto

Gene expression and splicing alterations analyzed by high throughput RNA sequencing of chronic lymphocytic leukemia specimens.

BackgroundTo determine differentially expressed and spliced RNA transcripts in chronic lymphocytic leukemia specimens a high throughput RNA-sequencing (HTS RNA-seq) analysis was performed.MethodsTen CLL specimens and five normal peripheral blood CD19+ B cells were analyzed by HTS RNA-seq. The library preparation was performed with Illumina TrueSeq RNA kit and analyzed by Illumina HiSeq 2000 sequencing system.ResultsAn average of 48.5 million reads for B cells, and 50.6 million reads for CLL specimens were obtained with 10396 and 10448 assembled transcripts for normal B cells and primary CLL specimens respectively. With the Cuffdiff analysis, 2091 differentially expressed genes (DEG) between B cells and CLL specimens based on FPKM (fragments per kilobase of transcript per million reads and false discovery rate, FDR q &lt; 0.05, fold change &gt;2) were identified. Expression of selected DEGs (n = 32) with up regulated and down regulated expression in CLL from RNA-seq data were also analyzed by qRT-PCR in a test cohort of CLL specimens. Even though there was a variation in fold expression of DEG genes between RNA-seq and qRT-PCR; more than 90 % of analyzed genes were validated by qRT-PCR analysis. Analysis of RNA-seq data for splicing alterations in CLL and B cells was performed by Multivariate Analysis of Transcript Splicing (MATS analysis). Skipped exon was the most frequent splicing alteration in CLL specimens with 128 significant events (P-value &lt;0.05, minimum inclusion level difference &gt;0.1).ConclusionThe RNA-seq analysis of CLL specimens identifies novel DEG and alternatively spliced genes that are potential prognostic markers and therapeutic targets. High level of validation by qRT-PCR for a number of DEG genes supports the accuracy of this analysis. Global comparison of transcriptomes of B cells, IGVH non-mutated CLL (U-CLL) and mutated CLL specimens (M-CLL) with multidimensional scaling analysis was able to segregate CLL and B cell transcriptomes but the M-CLL and U-CLL transcriptomes were indistinguishable. The analysis of HTS RNA-seq data to identify alternative splicing events and other genetic abnormalities specific to CLL is an added advantage of RNA-seq that is not feasible with other genome wide analysis