1,721,313 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Production and characterization of cellulolytic enzymes from agro industrial residues by Aureobasidium pullulans LB 83 and its respective proteomic analysis
No full textCom a crescente demanda por combustíveis renováveis e bioprodutos, objetivando o desenvolvimento sustentável, a biomassa lignocelulósica tornou-se um importante composto a ser aplicado em bioprocessos devido ao seu baixo custo e alta disponibilidade. O objetivo deste trabalho foi estudar a produção de enzimas celulolíticas a partir do microrganismo Aureobasidium pullulans utilizando diferentes resíduos lignocelulósicos Esses sub-produtos foram submetidos a pré-tratamento alcalino para redução de lignina e uso como fonte de carbono para estudo da produção de celulase sob cultivo submerso. O potencial de produção de celulase de A. pullulans foi avaliado pelo método de placas, utilizando 0,5% (m/v) de fontes de carbono (Carboximetilcelulose (CMC) e xilooligossacarideos (XOS)). As zonas hidrolíticas foram de 2,36 e 2,49 para CMC e XOS, respectivamente, indicando seu possível uso para investigações posteriores. A CMC foi utilizada na fermentação inicial como fonte de carbono para obtenção do tempo ótimo de fermentação e atividade enzimática, sequentemente foram usadosoutros substratos como fontes primárias de carbono. Diferentes fontes de nitrogênio sintético e não sintético foram testadas para otimização da produção de celulase. Por fim a concentração de células, pH e temperatura também foram usadas como parâmetro. Verificou-se que bagaço de cana-de-açúcar, fontes de nitrogênio não sintéticas combinadas e inóculo de 1,6x106 UFC a 50ºC da reação enzimática e pH 5,5 possuia a melhor atividade (8,84 para CMCase e 3,457 para FPase). Os resultados demonstram a potencialidade desse microrganismo de produzir enzimas celulolíticas viáveis para estudos na área de análises proteômicas e possíveis aplicações industriais. Nas análises proteômicas foram identificadas a proporção de proteínas totais e CAZymas. O total de 464 proteínas, das quais 38 correspondiam a CAZymas (8,18% do total de proteínas). Dentre as CAZymes foram encontrados 21 glicosídeo hidrolases (55,26%), 12 glicosídeo hidrolases com módulo de ligação de carboidratos (31,58%), 4 carboidratos esterases (10,53%), uma glicosil transferase (2,63%), como demonstrado no gráfico da Figura 23. Isso sugere que o Aureobasidium pullulans é um microrganismo muito versátilna produção de suas proteínas e, principalmente, CAZymas, que ao comparado a outros trabalhos com microrganismos observa-se que possí menos proporção em relação a proteína total, porém sua atividade maior sugere que trata-se de enzimas com maior atividade de reação no substrato lignocelulósico.With the growing demand for renewable fuels and bioproducts, aiming at sustainable development, lignocellulosic biomass has become an important compound to be applied in bioprocesses due to its low cost and high availability. The objective of this work was to study the production of cellulolytic enzymes from the microorganism Aureobasidium pullulans using different lignocellulosic residues. These by-products were subjected to alkaline pretreatment to reduce lignin and use as a carbon source to study cellulase production under submerged culture. The cellulase production potential of A. pullulans was evaluated by the plate mathod, using 0.5% (m/v) of carbon sources (Carboxymethylcellulose (CMC) and xylooligosaccharides (XOS)). The hydrolytic zones were 2.36 and 2.49 for CMC and XOS, respectively, indicating their possible use for further investigations. CMC was used in the initial fermentation as a carbon source to obtain the optimum fermentation time and enzymatic activity, followed by the use of other substrates as primary carbon sources. Different sources of nitrogen synthetic and non-synthetic were tested to optimize cellulase production. Finally, cell concentration, pH and temperature were also used as a parameter. It was found that sugarcane bagasse, combined non-synthetic nitrogen sources and inoculum of 1.6x106 CFU at 50ºC of the enzymatic reaction and pH 5.5 had the best activity (8.84 for CMCase and 3.457 for FPase). The results demonstrate the potential of this microorganism to produce cellulolytic enzymes for studies in the area of proteomic analysis and industrial applications. In the proteomic analyzes, the proportion of total proteins and CAZymes was identified. A total of 464 proteins were obtained, of which 38 corresponded to CAZymes (8.18% of the total proteins). Among CAZymes, 21 glycoside hydrolases (55.26%), 12 glycoside hydrolases with carbohydrate binding module (31.58%), 4 carbohydrate esterases (10.53%), one glycosyl transferase (2.63%) were found. This suggests that Aureobasidium pullulans is a very versatile microorganism in the production of its proteins and, mainly, CAZymes, which when compared to other studies with microorganisms it is observed that it has less proportion in relation to the total protein, however its greater activity suggests that it enzymes with greater reaction activity in the lignocellulosic substrate
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
Production and characterization of exopolysaccharide lasiodiplodan by Lasiodiplodia theobromae from sugar cane bagasse cellulosic hydrolysate
No full textA conversão da biomassa lignocelulósica para açúcares de segunda geração (2G) é crucial para a produção de biocombustíveis e produtos de maior valor agregado. No entanto, devido à sua natureza recalcitrante da biomassa lignocelulósica, o pré-tratamento é um passo essencial para aumentar a acessibilidade das enzimas celulolíticas à hemicelulose e à celulose para obter açúcares 2G. Neste estudo, o bagaço de cana-de-açúcar foi pré-tratado com ácido nítrico e hidróxido de sódio sequencialmente. O bagaço submetido à pré tratamento sequencial ácido-base levou a produzir uma polpa celulósica que reteve 92,33% da celulose e eliminou 70,63% de lignina. A polpa celulósica obtida foi hidrolisada enzimaticamente (10% de sólidos totais) por Cellic Ctec 2, Novozyme (Curitiba, Brasil), apresentando um rendimento de 72,05%, com 67,89 g/L de glicose. Foi avaliado o potencial biotecnológico do hidrolisado celulósico de bagaço de cana-de-açúcar (HCBCA) suplementado com extratos de farelo de soja e arroz na produção de lasiodiplodana (LAS) por Lasiodiplodia theobromae CCT 3966, utilizando DCCR 22 para o estudo da relação carbono/nitrogênio, gerando modelos matemáticos com níveis de confiança de 95% e p valores menores que 0,05. As melhores condições com a suplementação de farelo de soja possibilitaram a obtenção 16,2 g/L LAS e 8,34 g/L biomassa celular, enquanto a suplementação com farelo de arroz produziu 22,03 g/L e 14,03 g/L às 120 h, respectivamente. Algumas propriedades das frações de LAS obtidas foram caracterizadas, tais como alto grau de pureza, baixa solubilidade, comportamento pseudoplástico; além disso, usou-se técnicas de SEM, DSC e GPC, que demonstraram novas características, enquanto as análises de XRD e FTIR demonstraram composição e valores semelhantes às reportadas na literatura para LAS produzida por L. theobromae.The conversion of lignocellulosic biomass to second generation (2G) sugars is crucial for production of biofuels and value added products. However, due to their recalcitrant nature of lignocellulosic biomass, pretreatment is an essential step to increase in increasing the accessibility of cellulolytic enzymes to hemicellulose and cellulose to obtain fermentable 2G sugars. In this study, sugarcane bagasse was pretreated with nitric acid and sodium hydroxide sequentially. The bagasse submitted to sequential acid-base pretreatment led to the production of cellulosic pulp that retained 92.33% of cellulose and eliminated 70.63% of lignin. The obtained cellulosic pulp was enzymatically hydrolyzed (10% of total solids) by Cellic Ctec 2, Novozyme (Curitiba, Brazil), showed a yield of 72.05%, with 67.89 g/L of glucose. The biotechnological potential of cellulosic hydrolyzate supplemented with soybean and rice bran extracts for lasiodiplodan (LAS) production by Lasiodiplodia theobromae CCT 3966 was evaluated by using DCCR 22 to study the carbon/nitrogen relationship, generating mathematical models with 95% confidence levels and p-values less than 0.05. The best conditions with soybean bran supplementation allowed to obtain 16.2 g/L of LAS and 8.34 g/L of cell biomass, while supplementation with rice bran produced 22.03 g/L and 14.03 g/L at 120 h, respectively. Some properties from obtained LAS fractions were characterized, such as high purity, low solubility, pseudoplastic behaviour. In addition, SEM, DSC and GPC techniques were used, demonstrated new characteristics, whereas the XRD and FTIR analyzes demonstrated composition and similar values to those reported in the literature for LAS produced by L. theobromae
Heat transfer modeling of laser cladding process – role of location of injection of powder particles
Full text linkPaper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.A two-dimensional heat transfer model is developed to study the role of the location of injection of powder particles in to the melt pool stirred by convection due to thermo capillary force during the powder blown laser cladding process. The effects of both positive and negative surface tension coefficients and the absorbed laser power are studied. For the positive surface tension coefficients the powder is injected in a region where the flow velocity is in the direction of powder injection velocity and therefore the particles travel a little deeper into the melt pool. For negative surface tension coefficients the powder is injected in a region where the flow in opposite to the direction of injection velocity and the particles always stay very close to the melt pool surface. To solve the discretized governing equations finite volume method in a multiblock non-orthogonal grid system with collocated primitive variable approach is utilized.cf201
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
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