33 research outputs found

    Study of poly(o-Ethoxyaniline) interactions with herbicides and evaluation of conductive polymer potential used in electrochemical sensors

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    Interactions of four aromatic nitrogen-heterocyclic herbicides (atrazine, imazaquin, metribuzin and paraquat) with the conductive polymer poly(o-ethoxyaniline)-POEA, were studied with atomic force microscopy (AFM), UV-visible spectrophotometry (UV-Vis) and electrochemical impedance spectroscopy. AFM profiles of self-assembled (SA) films of POEA revealed that the polymer surface became rougher (on the nanoscale) when exposed to atrazine, imazaquin and metribuzin, but slightly smoother in contact with paraquat. This suggested that specific chemical interactions, possibly electroscopic, have occurred between nitrogen atoms in the polymer chain and the dissimilar groups in the various herbicide molecules, during adsorption of the latter onto the film. The UV-Vis analyses indicated a stronger interaction of POEA in solution with imazaquin, that has a special importance for the intended application. Sensors produced by coating microelectrodes with SA films of POEA were used to perform impedance spectroscopy in aqueous solutions of each herbicide. With the resulting data, it was possible to distinguish and set detection limits for each herbicide in water, corroborating AFM and UV-Vis results

    LC‐HRMS for the Identification of β‐Carboline and Canthinone Alkaloids Isolated from Natural Sources

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    β-carboline and canthinone alkaloids are widely distributed in the Angiosperms. Due to their diverse biological activities, the structures of these alkaloids have been used as important models for the synthesis of novel therapeutic drugs. Combining high-performance liquid chromatography (HPLC) with high-resolution mass spectrometry (HRMS) has provided a valuable tool in the analysis of these alkaloids in, for example, plants, insects, marine creatures, human tissues and body fluids. In this review, we summarized the main β-carboline and canthinone alkaloids studied by liquid chromatography high-resolution mass spectrometry (LC-HRMS) associated with mass analyzers, molecular weight information, mass fragmentation and biological activities, presenting an overview of increasing interest for carboline alkaloids study by LC-HRMS

    Pervasive gaps in Amazonian ecological research

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    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

    Educomunicação e suas áreas de intervenção: Novos paradigmas para o diálogo intercultural

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    oai:omp.abpeducom.org.br:publicationFormat/1O material aqui divulgado representa, em essência, a contribuição do VII Encontro Brasileiro de Educomunicação ao V Global MIL Week, da UNESCO, ocorrido na ECA/USP, entre 3 e 5 de novembro de 2016. Estamos diante de um conjunto de 104 papers executivos, com uma média de entre 7 e 10 páginas, cada um. Com este rico e abundante material, chegamos ao sétimo e-book publicado pela ABPEducom, em seus seis primeiros anos de existência. A especificidade desta obra é a de trazer as “Áreas de Intervenção” do campo da Educomunicação, colocando-as a serviço de uma meta essencial ao agir educomunicativo: o diálogo intercultural, trabalhado na linha do tema geral do evento internacional: Media and Information Literacy: New Paradigms for Intercultural Dialogue

    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

    Pervasive gaps in Amazonian ecological research

    Get PDF
    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

    MARX E O CRISTIANISMO

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    Nesse primeiro centenário do nascimento de KarI Marx o tema "Marx e o Cristianismo", que parecia ter encontrado seu lugar definitivo nas prateleiras da literatura marxológica renasce, ao menos no Ocidente, para uma surpreendente atualidade. Para Marx o enigma do Cristianismo — ou sua "essência", para falar como Feuerbach — estava completamente desvendado e sua sorte definitivamente julgada e selada pela história
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