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Metabolic pathways of Amino Acids, Monosaccharides and Organic Acids in Soils assessed by Position-Specific Labeling
No full textMetabolic pathways of Amino Acids, Monosaccharides and Organic Acids in Soils assessed by Position-Specific Labeling
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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
Microbial Metabolic Flux Analysis Using Position-Specific 13C-Labelled Glucose and Fragment 13C Analysis of Plfa
No full textVariations 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
Microbial carbon recycling: an underestimated process controlling soil carbon dynamics – Part 2: A C<sub>3</sub>-C<sub>4</sub> vegetation change field labelling experiment
No full textThe mean residence times (MRT) of different compound classes of soil organic
matter (SOM) do not match their inherent recalcitrance to decomposition. One
reason for this is the stabilization within the soil matrix, but recycling,
i.e. the reuse of "old" organic material to form new biomass may also play
a role as it uncouples the residence times of organic matter from the
lifetime of discrete molecules in soil.
We analysed soil sugar dynamics in a natural 30-year old labelling
experiment after a wheat-maize vegetation change to determine the extent of
recycling and stabilization by assessing differences in turnover dynamics
between plant and microbial-derived sugars: while plant-derived sugars are
only affected by stabilization processes, microbial sugars may be subject to
both, stabilization and recycling. To disentangle the dynamics of soil
sugars, we separated different density fractions (free particulate organic
matter (fPOM), light occluded particulate organic matter (≤ 1.6 g cm−3; oPOM1.6), dense occluded particulate organic matter
(≤ 2 g cm−3; oPOM2) and mineral-associated organic matter (> 2 g cm−3; mineral)) of a silty loam under long-term wheat and maize
cultivation. The isotopic signature of neutral sugars was measured by high
pressure liquid chromatography coupled to isotope ratio mass spectrometry
(HPLC/IRMS), after hydrolysis with 4 M Trifluoroacetic acid.
While apparent MRT of sugars were comparable to total
organic carbon in the bulk soil and mineral fraction, the apparent MRT of
sugar carbon in the oPOM fractions were considerably lower than those of the
total carbon of these fractions. This indicates that oPOM formation was
fuelled by microbial activity feeding on new plant input. In the bulk soil,
MRT of the mainly plant-derived xylose were significantly lower than those
of mainly microbial-derived sugars like galactose, rhamnose, fucose,
indicating that recycling of organic matter is an important factor
regulating organic matter dynamics in soil
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
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