18crown6
Mostrando 1-12 de 34 artigos, teses e dissertações.
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1. Determination of Ethyl Carbamate in Commercial Sweetened Sugar Cane Spirit by ESI-MS/MS Using Modified QuEChERS and 18-Crown-6/Trifluoroacetic Acid Spiking Additives
A fast, sensitive, and selective direct injection electrospray tandem mass spectrometry (DI ESI MS/MS) method that is able to quantify ethyl carbamate in commercial sweetened sugar cane spirit is described. The preparation method uses a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) with potassium carbonate added to sweetened sugar cane
Journal of the Brazilian Chemical Society. Publicado em: 2022
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2. Efectos del fuego en el arbolado de un bosque tropical de pino y en el de una selva baja caducifolia en Villaflores, Chiapas
Abstract It is expected an increase of forest fires world-wide because of global warming. So is important the study of fire ecology and fire effects in different ecosystems. In Villaflores, Chiapas, Mexico, are conducted efforts towards the integral fire management. There was studied a Pinus oocarpa Schiede forest, as well as a tropical dry forest, affected
Ciênc. Florest.. Publicado em: 02/12/2019
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3. ECONOMIC PERFORMANCE OF LOBLOLLY PINE STANDS IN SOUTHERN BRAZIL AS A RESULT OF DIFFERENT CROWN THINNING INTENSITIES1
RESUMO Aproximadamente 1,6 milhões de hectares são cultivados com Pinus no sul do Brasil, principalmente com Pinus taeda L. Mais de um terço dos povoamentos pertencem a produtores de toras independentes, cujos objetivos são maximizar os resultados econômicos. Neste estudo, um experimento de desbastes foi avaliado durante um período de produção de 30
Rev. Árvore. Publicado em: 13/06/2019
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4. Fast Triacylglycerol Screening and Semi-Quantitative Analysis of Fatty Acids in Commercial Oils by DIMS with 18-Crown-6 Ether/Trifluoracetic Acid Dopants
Vegetable oil analyses, especially due to the complexity of the oil components, are commonly laborious, requiring several analytical techniques. In this work, electrospray ionization mass spectrometry with direct injection (DIMS), along with 18-crown-6 ether (crown ether) chelating agent and trifluoroacetic acid (TFA), was used to characterize and semi-quant
J. Braz. Chem. Soc.. Publicado em: 2019-02
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5. Isolated trees with high crown coverage and densities increase pasture seed rain
ABSTRACT Pasture and crop lands restrict seed dispersal near remnant forest fragments, especially by restricting the movements of dispersal agents and limiting propagule dispersal. Some factors can improve seed dispersal in open areas, such as the presence of high numbers of isolated trees in close proximity to forest fragments. We sought to determine if: (i
Acta Bot. Bras.. Publicado em: 2016-09
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6. Four species of the new Amazonian sharpshooter Daedaloscarta gen. nov. (Insecta: Hemiptera: Cicadellidae)
Four new species, Daedaloscarta erwini sp. nov. (Peru: Loreto), D. maculata sp. nov. (Brazil: Amazonas), D. mene sp. nov. (Ecuador: Orellana), and D. redacta sp. nov. (Brazil: Amazonas) are described and placed in the new genus Daedaloscarta gen. nov. Species of the new genus can be readily distinguished from other Cicadellini genera by their: (1) dark brown
Zoologia (Curitiba). Publicado em: 2012-12
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7. Serrapilheira aplicada como biomonitor na avaliação do bosque urbano do Instituto de Pesquisas Energéticas e Nucleares, São Paulo,SP / Litterfall as biomonitors applied the evaluation of urban forest of the Nuclear and Energy Research Institute, São Paulo, SP
Several processes are considered responsible for ecosystems maintaining. Among them we can highlight mineral cycling that corresponds to the cycle of chemical elements that flow between the biotic compartments, leaves and litterfall, and abiotic, atmosphere and soil. These chemical elements accumulate of the active form through the absorption in the tissues
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 10/11/2011
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8. Mesiodistal width and proximal enamel thickness of maxillary first bicuspids
This study aimed at evaluating measurements relative to the mesiodistal crown width and enamel thickness of maxillary first bicuspids. The sample consisted of 40 extracted sound bicuspids (20 right and 20 left), selected from white patients (mean age: 23.7 ± 4.2 years), who were treated orthodontically with tooth extraction at a private clinic in São Paulo
Brazilian Oral Research. Publicado em: 2010-03
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9. Efeito da clorexidina e flúor na resistência coesiva da estrutura dental irradiada e não irradiada
Radiation therapy significantly reduces the resistance of the tooth structure and the damage is potentially higher in the organic matrix. The use of products that promote the stabilization of collagen and / or agents to intensify the cross-links may provide less damage to the resistance of teeth irradiated. This study aimed analyze the effect of the use of c
Publicado em: 2010
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10. DESENVOLVIMENTO INICIAL DE UM PLANTIO MISTO DE Eucalyptus urograndis E Acacia mearnsii EM SISTEMA AGROSSILVICULTURAL / INITIAL GROWTH AND PRODUCTIVITY IM MONOSPECIFIC AND MIXED STANDS OF Eucalyptus urograndis AND Acacia mearnsii IN AN AGROFORESTRY SYSTEM
Understanding the initial development in consortiated systems are vital to decide about practices to obtain a sustainable productivity, in relation to environmental resources in an agrossilvicultural site. Due to this, this study had as objective: - to evaluate the agricultural productivity in agroforestry systems with different arrangements of the forest sp
Publicado em: 2010
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11. Atividade de meliponíneos (Hymenoptera: Apidae) em ambiente protegido / Meliponin activity (Hymenoptera: Apidae) into protected environment
In order to use tribe Meliponin bees into protected environment pollination programs, this work has aimed to evaluate different Meliponin species into greenhouse. The study was made at UFV, using a greenhouse, with an area of 115,2 m, 3,5 m height in the sides and 5,2 m in the upper part. Initially six Meliponin species were studied (Melipona quadrifasciata,
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 20/04/2009
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12. Caracterização da capacidade fotossintética e da condutância estomática em sete clones comerciais de Eucalyptus e seus padrões de resposta ao déficit de pressão de vapor / Photosynthetic capacity and stomatal conductance characterization for seven commercial Eucalyptus clones and their variation due to vapor pressure deficit
This study aimed to characterize the physiological variables related to photosynthesis, in seven commercial Eucalyptus clones with high productivity, by evaluating maximum photosynthetic capacity (Amax), and the response of photosynthesis (A), stomatal conductance (gs) and transpiration (E) to Vapor Pressure Deficit (VPD). A trial was installed in 2004, at E
Publicado em: 2009