1,720,954 research outputs found
Crescimento vegetativo e fitoquímica de Zephyranthes irwiniana (Ravenna) Nic. García cultivada in vitro e em casa de vegetação
Get PDFDissertação (mestrado) — Universidade de Brasília, Instituto de Ciências Biológicas, Departamento de Botânica, Programa de Pós-Graduação em Botânica, 2023.A família Amaryllidaceae J. St.-Hil. é conhecida pelo potencial ornamental e pela capacidade
de sintetizar diversos alcaloides, como a galantamina, um potente medicamento utilizado no
tratamento dos sintomas da Doença de Alzheimer - DA. No entanto, algumas espécies dessa família
possuem baixa taxa de multiplicação e estão em situação de vulnerabilidade ou risco de extinção.
Diante desse conjunto de fatores, é importante o desenvolvimento de métodos de propagação
sustentáveis para domesticação, produção de biomassa e metabólitos secundários de Amaryllidaceae.
O objetivo desse trabalho foi analisar, pela primeira vez, o crescimento vegetativo e a fitoquímica de
compostos potenciais para o tratamento da DA, em resposta às variações da concentração de sacarose
e do uso do carvão ativado no meio de cultura, da espécie Zephyranthes irwiniana (Ravenna) Nic.
García, propagada por semente, in vitro e em casa de vegetação. Após 120 dias da germinação in
vitro, os bulbilhos resultantes foram separados em 6 tratamentos (T1-T6) e colocados em meio básico
MS (4,4 gL-1) e Phytagel (1,5gL-1) para um segundo cultivo, onde os tratamentos T1-T2, T3-T4, e
T5-T6, foram suplementados, respectivamente, com 30gL-1, 45gL-1 e 60gL-1 de sacarose, e os
tratamentos T2, T4 e T6, com 1,0gL-1 de carvão ativado. Foi utilizado ANOVA e teste de Tukey
(5%) para análises estatísticas. Após 150 dias do segundo cultivo in vitro e 270 dias do cultivo em
casa de vegetação, constatou-se que o incremento de biomassa dos indivíduos cultivados em casa de
vegetação foi superior aos indivíduos cultivados in vitro, no entanto, tiveram os menores rendimentos
de extração etanólica. No cultivo in vitro, o aumento da concentração de sacarose influenciou
positivamente no aumento da biomassa seca e fresca, e no número de raízes, não influenciando o
número de folhas e tamanho das folhas e raízes. O carvão ativado (CA) influenciou positivamente no
tamanho das folhas e das raízes, e negativamente no número de raízes, não influenciando o
incremento de biomassa fresca e seca, nem o número de folhas. As análises por CG-EM indicaram
grande variação na abundância de α-terpenil-acetato, linoleato de etila, clionasterol e licorina entre
os tratamentos, sendo as concentrações máximas foram, respectivamente, 53,06% (Folha, T2),
38,68% (Bulbo, T7), 14,34% (Raiz, T6) e 2,57% (Folha, T5). Testes de histolocalização utilizando o
reagente de Dragendorff indicaram a presença de alcaloides no clorênquima das folhas,
principalmente nos bordos foliares, e nos catafilos dos bulbos, próximos a epiderme voltada para
parte externa do bulbo. Por fim, o presente estudo forneceu novas evidências de que a constituição
do meio de cultura influência diretamente e é eficaz para obter melhores resultados no crescimento
vegetativo e na fitoquímica.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) e Fundação de Apoio à Pesquisa do Distrito Federal (FAPDF).The Amaryllidaceae J. St.-Hil. Family is known for its ornamental potential and ability to
synthesize several alkaloids, such as galantamine, a potent medication used to treat the symptoms of
Alzheimer's Disease - AD. However, some species of this family have a low rate of multiplication
and are vulnerable or at risk of extinction. Given these factors, it is important to develop sustainable
propagation methods for domestication, biomass and secondary metabolites production of
Amaryllidaceae. The objective of this work was to analyze, for the first time, the vegetative growth
and phytochemistry of potential compounds for the treatment of AD, in response to variations in
sucrose concentration and the use of activated carbon in the culture medium of the species
Zephyranthes irwiniana (Ravenna) Nic. García, propagated by seed, in vitro and in a greenhouse.
After 120 days of in vitro germination, the resulting bulbils were separated into 6 treatments (T1-T6)
and placed in basic medium MS (4.4 gL-1) and Phytagel (1.5gL-1) for a second culture, where the
treatments T1-T2, T3-T4, and T5-T6 were supplemented, with 30gL-1, 45gL-1 and 60gL-1 of
sucrose, respectively, and treatments T2, T4 and T6, with 1.0gL-1 of activated charcoal ANOVA
and Tukey's test (5%) were used for statistical analyses. After 150 days of the second in vitro
cultivation and 270 days of the cultivation in a greenhouse, it was observed that the biomass increases
of the individuals grown in a greenhouse was higher than the individuals cultivated in vitro, however,
they had the lowest ethanolic extraction yields. In vitro cultivation, the increase in sucrose
concentration positively influenced the increase in dry and fresh biomass, and in the number of roots,
not influencing the number of leaves and size of leaves and roots. Activated charcoal (AC) had a
positive influence on leaf and root size, and a negative influence on the number of roots, not
influencing the increase of fresh and dry biomass, nor the number of leaves. GC-MS analyses
indicated great variation in the abundance of α-terpenyl-acetate, ethyl linoleate, clionasterol and
lycorine between treatments, with the maximum concentrations was 53.06% (Leaf, T2), 38.68%
(Bulb, T7), 14.34% (Root, T6) and 2.57% (Leaf, T5), respectively. Histolocalization tests using the
Dragendorff reagent indicated the presence of alkaloids in the chlorenchyma of the leaves, mainly on
the leaf edges, and in the cataphylls of the bulbs, close to the epidermis facing the outer part of the
bulb. Finally, the present study provided new evidence that the constitution of the culture medium
directly influences and is effective to obtain better results in vegetative growth and phytochemistry.Instituto de Ciências Biológicas (IB)Departamento de Botânica (IB BOT)Programa de Pós-Graduação em Botânic
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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