1,721,008 research outputs found
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
Prospection of antifungal agents of agronomic interest in species of the genus Penicillium
No full textThe genus Penicillium has several species already identified as producers of bioactive
molecules derived from their secondary metabolism, showing prominence in several
biological activities of interest such as antifungal activity. More and more, several
countries have been using microorganisms, especially fungi, as agents for the
biocontrol of diseases caused by phytopathogenic fungi, since these are considered
natural agents and with great efficiency in protecting economically valuable crops
worldwide. Bearing in mind the concern with the use of techniques that aim to preserve
cultures of economic value, such as the guarana crop, a plantation widely cultivated
for commercialization in several industrial sectors in the state of Amazonas and
harnessing the capacity of fungi, mainly of the genus Penicillium in producing bioactive
substances and its ability to act as a biocontrol agent this work aims to verify the
antifungal potential of different species of fungi of the genus Penicillium (MMSRG-020)
in combating the phytopathogenic fungus Fusarium decemcellulare (MMSRG-110)
through tests of antibiosis, as well as chemically analyzing the secondary metabolites
involved in the activities to be discovered. Antibiosis assays showed that the fungus
MMSRG-020 (Penicillium sp.) acted as a mycoparasite against the phytopathogenic
fungus MMSRG-110 (Fusarium decemcellulare), preventing its growth and causing the
phytopathogen to lose one of its main characteristics, which is the color of its mycelium,
such activity demonstrates the ability of MMSRG-020 to act as an important biocontrol
agent against the main phytopathogen of guarana through the process of
mycoparasitism. The analysis by mass spectrometry showed that in the different
culture media in which MMSRG-020 was cultivated, at retention point 6.28 it presented
a mass value of 299.2 (m/z), identified as the 4-Aminophyscion molecule
(C16H13NO5) , an anthraquinone, first recorded as a natural product isolated from the
fungus Dermocybe canaria (order Agaricales) and which in this work was identified for
the first time in the genus Penicillium, an identification that corroborates the elucidation
of possible important biological activities arising from this anthraquinone.
Keywords: Penicillium; secondary metabolism; biocontrol agentes; mass
spectrometry.O gênero Penicillium possui diversas espécies já identificadas como produtoras de
moléculas bioativas oriundas de seu metabolismo secundário, apresentando destaque
em diversas atividades biológicas de interesse como a atividade antifúngica. Cada vez
mais, diversos países vêm utilizando microrganismos, principalmente os fungos como
agentes de biocontrole de doenças causadas por fungos fitopatogênicos, já que estes
são considerados agentes naturais e com grande eficiência na proteção de culturas
de valor econômico em todo o mundo. Tendo em vista a preocupação no emprego de
técnicas que visem preservar culturas de valor econômico, como é o caso da cultura
do guaraná, plantação amplamente cultivada para comercialização em diversos
setores industriais no estado do Amazonas e atrelando a capacidade dos fungos,
principalmente do gênero Penicillium em produzir substâncias bioativas e sua
capacidade de atuar como agente de biocontrole este trabalho tem por objetivo
verificar o potencial antifúngico de diferentes espécies de fungos do gênero Penicillium
(MMSRG-020) no combate do fungo fitopatogênico Fusarium decemcellulare
(MMSRG-110) através de ensaios de antibiose, bem como analisar quimicamente os
metabólitos secundários envolvidos nas atividades a serem descobertas. Os ensaios
de antibiose demonstraram que o fungo MMSRG-020 (Penicillium sp.) atuou como um
micoparasita frente ao fungo fitopatogênico MMSRG-110 (Fusarium decemcellulare),
impedindo o seu crescimento e fazendo com que o fitopatógeno perdesse uma de
suas principais características que é a coloração de seu micélio, tal atividade
evidencia a capacidade de MMSRG-020 em atuar como um importante agente de
biocontrole frente ao principal fitopatógeno do guaraná através do processo de
micoparasitismo. As análises por espectrometria de massas demonstraram que nos
diferentes meios de cultura em que MMSRG-020 foi cultivado, este, no ponto de
retenção 6.28 apresentou um valor de massa 299.2 (m/z), identificado como a
molécula 4-Aminophyscion (C16H13NO5), uma antraquinona, primeiramente registrada
como um produto natural isolado do fungo Dermocybe canaria (ordem Agaricales) e
que neste trabalho foi identificada pela primeira vez no gênero Penicillium,
identificação esta que corrobora para a elucidação de possíveis atividades biológicas
importantes oriundas desta antraquinona.
Palavras-chave: Penicillium; metabolismo secundário; agentes de biocontrole;
espectrometria de massas
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
Metabolomic analysis of annonaceae species occurring in Manaus by mass spectrometry
No full textA medicinal plant is considered like any species that administered to man or animal,
by any means or form, exerts some therapeutic function and due to the great use of
these herbs, studies in search of their chemical substances were and are carried out
continuously. The Annonaceae family is widely known for its alkaloids that are present
in several species, however, there are still specimens whose chemical components
have not been fully elucidated. Thus, the aim of this study was to comparatively
recognize different species of plants from the Annonaceae family by means of mass
spectrometry. For this, five plant species belonging to the genus Annona, Duguetia,
Fusaea, Guatteria and Xylopia were collected, their extracts were obtained and
analyzed by Liquid Chromatography coupled to High Resolution Mass Spectrometry
(LC-HRMS/MS). Of the five plants, only the leaves of the species Guatteria discolor
were analyzed and the results presented showed the presence of four alkaloid
substances (puterine, oxoputerine, asimilobine and anonaine), the latter two being
unpublished for this species. Among the identified molecules, only puterine has not yet
had its biological activity elucidated, thus suggesting new studies for this substance.
Keywords: Annonaceae, alkaloids, Guatteria discolor, aporphinic and oxoaporphinic.Considera-se planta medicinal toda espécie que administrada ao homem ou animal,
por qualquer via ou forma, exerça alguma função terapêutica e devido ao grande uso
dessas ervas, estudos em busca de suas substâncias químicas foram e são realizados
continuamente. A família Annonaceae é amplamente conhecida pelos seus alcaloides
que estão presentes em diversas espécies, entretanto, ainda há exemplares cujos
componentes químicos ainda não foram totalmente elucidados. Deste modo, o
objetivo deste estudo foi reconhecer comparativamente diferentes espécies de plantas
da família Annonaceae por meio de espectrometria de massas. Para isso, foram
coletadas cinco espécies de plantas pertencentes ao gênero Annona, Duguetia,
Fusaea, Guatteria e Xylopia, seus extratos foram obtidos e analisados através da
cromatografia líquida acoplado a espectrometria de massa de alta resolução (LC HRMS/MS). Das cincos plantas, somente as folhas da espécie Guatteria discolor
foram analisadas e os resultados apresentados mostraram a presença de quatro
substâncias alcaloídicas (puterina, oxoputerina, asimilobina e anonaína), sendo estas
duas últimas inéditas para tal espécie. Dentre as moléculas identificadas, somente a
puterina ainda não possui a sua atividade biológica elucidada, sugerindo assim novos
estudos para essa substância.
Palavras chave: Annonaceae, alcaloides, Guatteria discolor, aporfínicos e
oxoaporfínicos
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
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