Nitrogen nutrition for lettuce effects of N-carriers and nitrification inhibition

Foram estudados, em condições de campo, os efeitos de diferentes fontes de N (ureia, nitrocálcio, sulfato de amônio, esterco de galinha e efluente de biodigestor), com (CNS) e sem (SNS) inibidor de nitrificação (nitrapirim), sobre a absorção de nitrogênio por alface (Lactuca sativa L.). O inibidor de nitrificação per se não mostrou efeito negativo sobre o crescimento das plantas. Entretanto, quando aplicado junto com a uréia, o inibidor reduziu significativamente o peso seco da alface; ocorreram também reduções significativas de peso quando o inibidor foi aplicado junto com esterco de galinha e nitrocálcio. O maior acúmulo de peso seco foi observado no tratamento esterco de galinha-SNS. O efluente de biodigestor mostrou ser uma fonte inadequada de N para as plantas. No tratamento esterco de galinha-SNS - foram observados acúmulos de N-NO3 (superiores ao tratamento Nitrocálcio-SNS), a níveis potencialmente tóxicos para nutrição humana. Constata-se que, no manejo atual, um excesso de N está sendo aplicado na cultura da alface no estado do Rio de Janeiro.A field experiment was carried out to study the effects of N-sources (urea, nitrocalcium, ammonium sulphate, chicken dung and biodigestor efluent) with (CNS) and without (SNS) a nitrification inhibitor (Nitrapyrin) on the dry weight and N-uptake of lettuce (Lactuca sativa, L.). The nitrification inhibitor per se had no negative effect on growth of lettuce. However, nitrification inhibitor + urea resulted in a sharp decrease in plant growth rates. The application of nitrocalcium and chicken dung + NS also resulted in decreases of lettuce dry weight. The highest rate of dry weight accumulation was induced by chicken dung - SNS. On the other hand, biodigestor effluent was shown to be a very poor source of N. The chicken dung treatment resulted in NO3- accumulation in lettuce at levels potencially harzardous to human health. It is proved that under the present cropping system, an excess of N is used by lettuce growers in Rio de Janeiro

A combined theoretical and experimental study of electronic structure and optical properties of β-ZnMoO4 microcrystals

In this paper, a combined theoretical and experimental study on the electronic structure and photoluminescence (PL) properties of beta zinc molybdate ( -ZnMoO4) microcrystals synthesized by the hydrothermal method has been employed. These crystals were structurally characterized by means of X-ray diffraction (XRD), Rietveld refinement, Fourier transform Raman (FT-Raman) and Fourier transform infrared (FT-IR) spectroscopies. Their optical properties were investigated by ultraviolet-visible (UV-vis) absorption spectroscopy and PL measurements. First-principles quantum mechanical calculations based on the density functional theory at the B3LYP calculation level have been carried out. XRD patterns, Rietveld refinement, FT-Raman and FT-IR spectra showed that these crystals have a wolframite-type monoclinic structure. The Raman and IR frequencies experimental results are in reasonable agreement with theoretically calculated results. UV-vis absorption measurements shows an optical band gap value of 3.17 eV, while the calculated band structure has a value of 3.22 eV. The density of states indicate that the main orbitals involved in the electronic structure of -ZnMoO4 crystals are (O2p-valence band and Mo 4d-conduction band). Finally, PL properties of -ZnMoO4 crystals are explained by distortions effects in octahedral [ZnO6] and [MoO6] clusters and inhomogeneous electronic distribution into the lattice with the electron density map

Mesoscopic modelling of 2-CN-PPV/PPV polymer LED

Although optoelectronic devices made of polymers are very attractive ones (low cost, easy to make), problems related to charge transport, exciton quenching, among others, can be an obstacle for their performance. The use of heterojunctions made of two polymers can be a strategy for improving the efficiency of polymer light emitting diodes (PLEDs) at low bias. Here we present a theoretical study of the influence of bilayer structure in a PLED made of PPV and 2-CN-PPV, by adopting a mesoscopic approach. Our results show that the presence of the polymer/polymer interface improves charge injection and leads to a confinement of charges near it, which will increase the number recombination events in the middle of the device compared to the equivalent single-layer PLEDs.Fundação para a Ciência e a Tecnologia (FCT) Programa Operacional “Ciência , Tecnologia, Inovação” POCTI/CTM/41574/2001, CONC-REEQ/443/EEI/2001 e SFRH/BD/22143/200

Identificación del índice de vulnerabilidad territorial a partir de modelos jerárquicos y heurísticos aplicando SOA

Auxiliar de InvestigaciónEn el proyecto se realiza el diseño y desarrollo de 4 servicios web implementando los modelos de toma de decisión (AHP, AHP FUZZY, ELECTRE y PROMETHEE), encargados de procesar datos obtenidos en campo en la primera fase del proyecto que se realizó a través de encuestas, formatos de entrevistas, talleres y metodologías de análisis. Los datos se procesaran de acuerdo al modelo de toma de decisión seleccionado, generando como resultado final un indicador de vulnerabilidad territorial.PregradoIngeniero de Sistema

Rosacea treatment update: recommendations from the global ROSacea COnsensus (ROSCO) panel

Dermatology-oncolog