FTTH EM REDES OPTICAS PASSIVAS

Esse estudo aborda um novo método de atuação em redes ópticas, cuja tecnologia gera uma maior disponibilidade de acesso à internet banda larga e aos serviços agregados ao simultaneamente. Esse método tem por finalidade o baixo custo para o usuário final, facilitando a ativação do circuito com qualidade, através da aplicação de abordagem FTTH (Fiber to the Home) e utilizando topologia de redes ópticas passivas (PON – Passive Optical Network). Este tipo de abordagem permite obter resultados de qualidade para redes em longas distancias através do uso de fibras óptica aplicadas em uma plataforma de multisserviços

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Human exposure to ultraviolet (UV) radiation leads photochemical excitation processes in the skin, causing problems to human health. The use of photoprotectors helps to minimize these intrinsic hazards. Benzophenone molecules stand out for the absorption of energy in the UVA and UVB range and structural changes in these, it is an area of ​​interest to obtain safer and more effective molecules. This work applied the full factorial design methodology 24 in an investigation by molecular modeling using semi-empirical method PM7, in order to evaluate the impact generated on the decrease of the energy GAP with the insertion of OH (level +) and H (level –-). The results showed unfavorable and favorable contributions between interactions and in the main effect, and the compounds disubstituted in ortho and para position for the same aromatic ring showed a better percentage of contribution, indicating that these conditions are relevant for greater reactivity compared to the others. Thus, we conclude that the use of the experimental planning methodology is an ally in obtaining information for planning new protective filtersmore stable and safe

Physiological and productive performance of papaya plants irrigated in a semiarid environment

Papaya tree has great economic importance and potential of cultivation in semiarid environment. However, water scarcity in this region may inhibits photosynthetic activity and limit the production of this crop, being necessary to use strategies of irrigation management that rationalize water and allow the production of the plants without affecting photosynthetic activity. In this sense, this study aimed to evaluate the physiological and productive performance of papaya “Calimosa” under different water replacement rates in semiarid environment. Papaya plants were irrigated with four water replacement rates (50, 75, 100 and 125% ETo) from 30 days after transplant of seedlings to the experimental area.  At 10 months after transplant were realized evaluations of gas exchange and chlorophyll fluorescence, and at 12 months after transplant, it was started harvesting fruits to determine the yield. Water replacement rates significantly influenced the parameters of gas exchange of papaya with better results on rates of 125% ETo. However, application of water replacement rates of 100% ETo provide conditions adequate for the activity of gas exchange and better quantum efficiency of photosystem II, that contribute to fruit production in papaya. With rates less than 75% ETo occur drastic reductions in gas exchange, quantum efficiency of photosystem II, and fruit production of papaya, which impairs its cultivation in semiarid environments

As reformas trabalhistas: promessas e impactos na vida de quem trabalha

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Validation of the near infrared spectroscopy method for determining soil organic carbon by employing a proficiency assay for fertility laboratories

Current research indicates that near infrared (NIR) spectroscopy is the most promising alternative technique for the determination of soil organic carbon (SOC) in laboratories worldwide and that it may serve as a total or partial replacement for the tradi243293303The authors acknowledge Embrapa for financial support (MP3 03.12.03.010.00.00

Evapotranspiration mapping of commercial corn fields in Brazil using SAFER algorithm

SAFER (Simple Algorithm for Evapotranspiration Retrieving) is a relatively new algorithm applied successfully to estimate actual crop evapotranspiration (ET) at different spatial scales of different crops in Brazil. However, its use for monitoring irrigated crops is scarce and needs further investigation. This study assessed the performance of SAFER to estimate ET of irrigated corn in a Brazilian semiarid region. The study was conducted in São Desidério, Bahia State, Brazil, in corn-cropped areas in no-tillage systems and irrigated by central pivots. SAFER algorithm with original regression coefficients (a = 1.8 and b = –0.008) was initially tested during the growing seasons of 2014, 2015, and 2016. SAFER performed very poorly for estimating corn ET, with RMSD values greater than 1.18 mm d–1 for 12 fields analyzed and NSE values < 0 in most fields. To improve estimates, SAFER regression coefficients were calibrated (using 2014 and 2015 data) and validated with 2016 data, with the resulting coefficients a and b equal to 0.32 and –0.0013, respectively. SAFER performed well for ET estimation after calibration, with r2 and NSE values equal to 0.91 and RMSD = 0.469 mm d–1. SAFER also showed good performance (r2 = 0.86) after validation, with the lowest RMSD (0.58 mm d–1) values for the set of 14 center pivots in this growing season. The results support the use of calibrated SAFER algorithm as a tool for estimating water consumption in irrigated corn fields in semiarid conditions

Modeling Actual Evapotranspiration with MSI-Sentinel Images and Machine Learning Algorithms

The modernization of computational resources and application of artificial intelligence algorithms have led to advancements in studies regarding the evapotranspiration of crops by remote sensing. Therefore, this research proposed the application of machine learning algorithms to estimate the ETrF (Evapotranspiration Fraction) of sugar can crop using the METRIC (Mapping Evapotranspiration at High Resolution with Internalized Calibration) model with data from the Sentinel-2 satellites constellation. In order to achieve this goal, images from the MSI sensor (MultiSpectral Instrument) from the Sentinel-2 and the OLI (Operational Land Imager) and TIRS (Thermal Infrared Sensor) sensors from the Landsat-8 were acquired nearly at the same time between the years 2018 and 2020 for sugar cane crops. Images from OLI and TIR sensors were intended to calculate ETrF through METRIC (target variable), while for the MSI sensor images, the explanatory variables were extracted in two approaches, using 10 m (approach 1) and 20 m (approach 2) spatial resolution. The results showed that the algorithms were able to identify patterns in the MSI sensor data to predict the ETrF of the METRIC model. For approach 1, the best predictions were XgbLinear (R2 = 0.80; RMSE = 0.15) and XgbTree (R2 = 0.80; RMSE = 0.15). For approach 2, the algorithm that demonstrated superiority was the XgbLinear (R2 = 0.91; RMSE = 0.10), respectively. Thus, it became evident that machine learning algorithms, when applied to the MSI sensor, were able to estimate the ETrF in a simpler way than the one that involves energy balance with the thermal band used in the METRIC model

Aprendizagem científica em atividades no Centro de Ciências da UFJF

-Os estudantes das escolas que visitam diariamente o Centro de Cîências da UFJF embasam nossa investigação, através de experiências relatadas e indução à reflexão de questões do cotidiano, envolvendo conceitos incorporados, sejam pela educação escolar, sejam pela sua vivência do dia a dia. Observando seu comportamento, atitudes, postura, através de registro escrito em aplicação de questionários, e também fotos e filmes, pode-se traçar um diagnóstico de seu interesse e curiosidade pelas atividades científicas e educacionais desenvolvidas no Centro.Investiga-se a capacidade de abstração dos estudantes quanto aos fundamentos teóricos da ciência, bem como avalia-se sua participação durante o período da visita ao Centro de Ciências.Utilizam-se nesse estudo comparações entre conceitos expostos pelos alunos antes de uma explicação, identificando padrões referentes a etapas do seu desenvolvimento, e suas concepções a respeito da aplicação e utilidade dos conceitos científicos

CLASSIFICAÇÃO DE USOS DA TERRA POR ANÁLISE DISCRIMINANTE MULTIGRUPOS

A discriminação de diferentes usos da terra com base em dados orbitais é um procedimento amplamente utilizado, principalmente pela rapidez de processamento e baixo custo de realização, dependendo do sensor utilizado. Uma classificação mais acurada, utilizando muitas variáveis inter-relacionadas, referenciadas a uma localização específica, torna complexo o manuseio e interpretação desses dados. Dessa forma, o estudo teve por objetivo estabelecer relações entre registros espectrais nas diferentes bandas da imagem do satélite Landsat-5/TM, consideradas variáveis independentes, e os diferentes usos da terra, considerados como casos, por meio de análise multivariada. Foi realizada a calibração radiométrica e a retificação das imagens. Após os processamentos foram obtidos de maneira aleatória os valores de reflectância da superfície, para as seis bandas do satélite, excluindo da análise a banda correspondente ao infravermelho termal. Para a classificação dos usos da terra foi utilizada a análise discriminante multigrupos. A identificação das áreas ocupadas por vegetação arbórea e cursos d’água foram adequadamente discriminadas entre si e em relação às demais classes de uso da terra. Houve dificuldade na separação de diferentes tipos de usos relacionados à pastagem, devido às condições de déficit hídrico associada à resolução espectral do sensor