1,721,025 research outputs found
Auxotrophic Saccharomyces cerevisiae CEN.PK strains as new performers in ethanol production
No full textIn this work, the capacity to produce ethanol of auxotrophic strains belonging to the CEN.PK family of the yeast Saccharomyces cerevisiae has been investigated. Shake flask experiments were set up to study the ethanol production by the auxotrophic S. cerevisiae CEN.PK strains in terms of biomass and ethanol yield, the latter was evaluated on both glucose and biomass. The test was carried out in a rich-complex medium with 2 and 15 % w/v initial glucose concentration. The results obtained, compared with those of the prototrophic CEN.PK strain, indicated that the fermentative capacity of the auxotrophic strain in 2 % glucose was comparable at all to the prototrophic one, whereas using 15 % initial glucose, the auxotrophic CEN.PK strain exhibited a more than doubled ethanol yield on biomass. The fermentative capacity of both the prototrophic and the auxotrophic strain was also tested after having refreshed the exhausted medium with glucose to restore the initial 15 % concentration. In these conditions, the amount of ethanol produced by the auxotrophic strain per mass unit, resulted to be double with respect to the prototrophic one. In the light of these results, yeast culture based on auxotrophic CEN.PK, strains could be taken into consideration as culture capable to produce ethanol with a low amount of microbial cells and so potentially suitable to be used for ethanol production by immobilized system
Fed-batch production of endoglucanase with a recombinant industrial strain of the yeast Saccharomyces cerevisiae
Full text linkThe Saccharomyces cerevisiae Y306 strain was used as a host for the production of a heterologous endoglucanase coded by celA from Paenibacillus barcinonensis. The endoglucanase (EG-CelA) was expressed in S. cerevisiae using the cell-wall protein Pir4 as fusion partner to determine the secretion of the enzyme into the culture medium.The recombinant S. cerevisiae Y306 was cultivated in aerobic fed-batch culture in order to maximize the heterologous enzyme production while avoiding the occurrence of pyruvate overflow during glucose metabolism. Aiming at this, an exponential feeding policy was adopted to achieve high cell density cultivation (HCDC) at a constant specific growth rate of 0.16 h-1.The experimental results demonstrated that EG-CelA was efficiently secreted into the culture medium along the entire course of the fed-batch process as a growth linked product being expressed under the Pir4 promoter. The final titer in 2 L broth culture resulted 2.48 g, an amount in accordance with the best productions of cellulolytic enzymes, reported by other authors.Further, a simple unstructured, non segregated mathematical model was employed to highlight that in the HCDC system developed, the microbial mass grew following the set up profile along the entire time-course of process
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
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
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
- …
