1,720,994 research outputs found
AFLP protocol comparison for microbial diversity fingerprinting
No full textOver the last decade, several methods based on genomic DNA have been developed for the identification and genotyping of prokaryotic and eukaryotic organisms. These genomic methods differ regarding taxonomic range, discriminatory power, reproducibility, and ease of interpretation and standardization. The amplified fragment length polymorphism (AFLP) technique is a very powerful DNA fingerprinting technique for DNA of any source or complexity, varying in both size and base composition. In addition, this method shows high discriminatory power and good reproducibility allowing it to be efficient in discriminating at both the species and strain levels. The development and application of AFLP have allowed significant progress in the study of biodiversity and taxonomy of microorganisms. In the last years, the Applied Biosystems AFLP Microbial Fingerprinting Kit, now out of production, was widely used in various studies to perform AFLP characterization of selected bacteria strains (described by Vos et al. (Nucleic Acids Res 23(21):4407-4414, 1995)). Its replacement gives the possibility for laboratories to continue the use of the previous AFLP data as a reference for bacteria genetic fingerprinting analysis in biodiversity studies. To overcome this issue a result comparison, by using an improved AFLP protocol and the AFLP commercial kit, was performed. In particular, previous results on different species (Listeria monocytogenes, Lactobacillus plantarum, and Streptococcus thermophilus) obtained with the commercial kit were compared with the improved AFLP procedure to validate the protocol. When compared with the AFLP Microbial Fingerprinting Kit, the improved protocol shows high reproducibility, resolution, and overall, is a faster method with lower costs
Application of lactic acid fermentation to elderberry juice: Changes in acidic and glucidic fractions
No full text
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
Nonstarter lactic acid bacteria volatilomes produced using cheese components
Full text linkIn long-ripened cheese, flavor formation occurs during
ripening. The metabolism of lactic acid bacteria
(LAB) leads to the production of different compounds
that contribute to the flavor of cheese. The contribution
of LAB to the formation of cheese flavor has previously
been studied. However, the specific nonstarter LAB
(NSLAB) metabolic reactions in ripened cheese that
lead to the formation of flavor compounds remain unclear.
In ripened cheese, the nutrient sources available
include small peptides or amino acids, citrate, lactate,
free fatty acids, and starter LAB cell lysis products.
Thus, the aim of this study was to evaluate the ability
of NSLAB to produce volatile flavor compounds
by using an in vitro system that used only the nutrients
available in ripened cheese as the energy source.
Moreover, the potential contribution of the NSLAB
volatilome on total cheese flavor is discussed. For this
purpose, the production of volatile compounds on
cheese-based medium (CBM) and on starter LAB lysed
cell medium (LCM) by 2 Lactobacillus casei and 2 Lactobacillus
rhamnosus strains, previously isolated from
ripened Parmigiano Reggiano cheese, was investigated.
The generated volatile compounds were analyzed with
head-space gas chromatography mass spectrometry.
Overall, ketones, aldehydes, alcohols, and acids were
the most abundant compounds produced. Differences
in volatilome production were found between NSLAB
grown in LCM and CBM. The catabolic metabolism of
amino acids and fatty acids were required for NSLAB
growth on LCM. Conversely, pyruvate metabolism was
the main catabolic pathway that supported growth of
NSLAB in CBM. This study can be considered a first
step toward a better understanding of how microbiota
involved in the long ripening of cheese may contribute
to the development of cheese flavor
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
- …
