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

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

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

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

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

Dual-polarization nonlinear Fourier transform-based optical communication system

New services and applications are causing an exponential increase in Internet traffic. In a few years, the 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 Schrödinger 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 a 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

Quando ingressar na Universidade n?o ? o suficiente : viv?ncias dos estudantes de camadas populares no curso de Direito da UFOP.

Programa de P?s-Gradua??o em Educa??o. Departamento de Educa??o, Instituto de Ci?ncias Humanas e Sociais, Universidade Federal de Ouro Preto.No Brasil, gra?as ?s press?es de movimentos da sociedade civil e aos avan?os globais naspol?ticas de a??o afirmativa, os anos 2000 trouxeram significativo aumento do n?mero dejovens de camadas populares na universidade. Nesse contexto, a pesquisa teve como principalobjetivo investigar os fatores que influenciaram o ingresso e a perman?ncia de estudantes decamadas populares no curso de Direito da Universidade Federal de Ouro Preto, fortementeseletivo e com alto prest?gio social, com destaque para o papel familiar no sucesso escolar. Paraisso, analisou a trajet?ria escolar percorrida por tr?s estudantes at? o ingresso no curso, al?mdas principais oportunidades e desafios dos seus processos de escolariza??o e da viv?nciauniversit?ria. O referencial te?rico se baseou em produ??es do campo da Sociologia daEduca??o, especialmente nos trabalhos sobre sucesso e longevidade escolar de estudantes dosmeios populares e sobre suas condi??es de acesso e perman?ncia no Ensino Superior, comautores como Bourdieu, Lahire, Coulon, Portes, Zago e Nogueira. Al?m da pesquisabibliogr?fica e documental, para o reconhecimento das pr?ticas educativas familiares, dopercurso escolar, das estrat?gias de ingresso e afilia??o, e das expectativas para o futuro, oprincipal instrumento metodol?gico utilizado foi a entrevista. Foram entrevistadas tr?sestudantes do curso de Direito, do sexo feminino, ingressantes entre 2016 e 2019, com rendaper capitade at? 1,5 sal?rio m?nimo, al?m de um dos seus familiares: pai, m?e e av?. Asentrevistadas apresentam diferen?as significativas no que diz respeito ? configura??o familiare ? escolaridade dos pais. Os resultados demonstraram que houve participa??o ativa da fam?liana escolariza??o, mesmo com pouco conhecimento sobre a organiza??o dosistema escolar e,em alguns casos, com baixo capital escolar e falta de planejamento relativo ? escolariza??o. Asestudantes com apoio familiar criaram estrat?gias espec?ficas para ingressar no curso de Direito,ao buscarem escolas de Ensino M?dio de alto prest?gio e ingressarem anteriormente em cursosde gradua??o de menor concorr?ncia. Tiveram trajet?rias escolares lineares na educa??o b?sica,sem reprova??es e com poucas recupera??es. Al?m disso, foi poss?vel perceber que algunsprofessores exerceram pap?is importantes em suas vidas, que elas passaram por in?merassitua??es de supera??o e por uma adapta??o dolorosa ? universidade, com o enfrentamento dasensa??o de n?o pertencimento. Importante ressaltar que, para essas estudantes e suas fam?lias,as bolsas e os aux?lios concedidos pela universidade foram imprescind?veisIn Brazil, thanks to the pressure of civil society movements and the global advancements inaffirmative action politics, the 2000s brought a significant increase in the number of minoritiesin the universities. In that context, this research had the main goal of investigating the factorsthe influenced the admission and permanence of students of popular upbringing in the highlyselective and prestigious major of Law at the Universidade Federal de Ouro Preto, highlightingthe role of the students? families in their school success. To that end, we analyzed the schoolrecords of three students up to their admission on university majors, and the main opportunitiesand challenges of their schooling and university life. The theoretical references here utilizedwere based in productions of the fields of Education Sociology, specially on the works aboutschool success and the permanence of the students of popular upbringing and the conditions forthem to access and remain in higher education, from authors like Bourdieu, Lahire, CoulonPortes, Zago e Nogueira. Besides bibliographical and documental research, for the recognitionof the educational practices, of school records, of the strategies for admission and affiliation,and the expectations for the future, the mainmethodological instrument used in thisinvestigation was the interview. We interviewed three students of Law major of the femalegender, admitted between 2016 and 2019, with an income of up to 1,5 minimum wage. We alsointerviewed their families: father,mother, and grandmother. The interviewed students haddifferent family configurations and different parents? scholarity. The results of the researchshow that there was an active participation of the families on their schooling, even with littleknowledgeof the school system and, in some cases, little education and lack of planning of theschooling process. The students that had family support came up with specific strategies to beadmitted on the Law major, by searching prestigious high schools and participating previouslyin majors of lesser concurrence. They had linear school records in basic education, withoutfailures and few retake tests. Also, it was possible to notice that some teachers had importantparts, that they went through many overcoming situations and through a hard adaptation to theuniversity, the confrontation of the feeling of not belonging, for instance. It is important tohighlight that to these students and their families, the scholarships and aids given by theuniversities were indispensable

CONTRIBUTION OF NITROGEN AND PHOSPHATE FERTILIZER IN THE INITIAL GROWTH OF Toona ciliata and Eucalyptus grandis

The growth of forest species is affected by nutritional restrictions. Therefore, the objective of this study was to evaluate the contribution of nitrogen and phosphate fertilization to the initial growth of forest species implanted in field. For this purpose, two experiments were carried out for 11 months, using a randomized complete block design with four replications, in a 2 x 4 factorial arrangement: two forest species (Toona ciliata and Eucalyptus grandis), four nitrogen doses in Experiment I (0, 25, 50 and 75 kg ha-1 of N) and four phosphorus doses in experiment II (0, 50, 100 and 150 kg ha-1 of P2O5). The evaluated parameters were: plant height, diameter at breast height and leaf concentration of nutrients. The data were submitted to analysis of variance. Adjusted regression models were based on the applied amounts of nutrients. The contribution of nitrogen fertilization to growth in height and diameter was equal in forest species, indicating the dose of 47 kg ha -1 of nitrogen with higher growth in the average of the two parameters evaluated. Phosphate fertilization showed no response in the growth of forest species due to the adequate phosphorus content of the soil in which the experiment was conducted. The leaf concentrations of nitrogen and phosphorus were not altered by the respective nutrient doses applied in the forest species. However, higher nutrient concentrations were observed in T. ciliata, indicating higher nutritional requirement compared to E. grandi

Analogical modelling in science education.

Neste artigo, nos propusemos a investigar: (i) as etapas que podem ser usadas para guiar a proposi??o e o desenvolvimento de atividades de modelagem anal?gica no ensino de ci?ncias; e (ii) como atividades de modelagem anal?gica propostas com base naquelas etapas podem ter contribu?do para que os estudantes de ci?ncias vivenciassem os subprocessos do racioc?nio anal?gico. Para atender ao primeiro prop?sito, adaptamos as etapas apresentadas na literatura para o processo de modelagem de forma que possibilitassem a elabora??o, cr?tica e revis?o de modelos e analogias. Para atender ao segundo prop?sito, realizamos um estudo emp?rico no qual desenvolvemos uma sequ?ncia ensino sobre o tema dissolu??o, fundamentada na modelagem anal?gica. A sequ?ncia foi desenvolvida em uma turma de Qu?mica do primeiro ano do ensino m?dio e deu origem ao estudo de caso analisado neste artigo. Nossos resultados evidenciaram elementos espec?ficos das atividades de modelagem anal?gica que favoreceram a ocorr?ncia dos subprocessos de racioc?nio anal?gico, inclusive daqueles identificados como n?o espont?neos em estudos anteriores. Destacamos como uma das implica??es deste estudo, que a descri??o proposta para as etapas da modelagem anal?gica pode orientar professores e pesquisadores na proposi??o e condu??o de atividades voltadas para o ensino de ci?ncias, nas quais modelos e analogias s?o criados, criticados e revisados pelos estudantes, num processo em que os significados v?o sendo gradualmente negociados na tentativa de se compreender a entidade modelada.In this paper, we aimed at investigating: (i) the steps that can be used to guide the elaboration and the conduction of analogical modelling activities in science education; and (ii) the way in which the analogical modelling activities based on those steps may have contributed to science students? experience of the subprocesses of analogical reasoning. To address the first purpose, we adapted some stages for modelling found in the educational literature, so that they would make the development, review and revision of models and analogies possible. To address the second purpose, we conducted an empirical study. A teaching sequence about the dissolving process, based on analogical modelling, was producOrg. The sequence was taught in a first-year high school chemistry class, and the data collected supported the drawing of the case study analysed in this paper. Our results showed that specific elements of analogical modelling activities that supported the occurrence of the analogical reasoning sub-processes, including those identified as not spontaneous in previous studies. One of the implications of this study is that our description for analogical modelling steps can guide teachers and researchers on designing and conducting science teaching activities in which models and analogies could be created, criticised and reviewed by students, in a process in which meanings are being gradually negotiated in an attempt to understand the entity modellOrg

Influencia del ejercicio físico en la percepción de calidad de vida de los niños/as con parálisis cerebral y de sus progenitores

El objetivo central de esta investigación es conocer como el Ejercicio Físico (EF) influye en la CV de estos niños/as, y saber cuál es la percepción que tienen los progenitores de los niños/as con PC, acerca del EF que practican, el bienestar que éste produce y su influencia en vida de sus hijos/as.Ciencias de la Actividad Física y del Deport