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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
Effects of artificial disturbance on quantity and biochemical composition of organic matter in sediments of a coastal lagoon
No full textThe eutrophication of the coastal lagoon of Burano (Tuscany, Italy) produces periodic
toxic-anoxic events. The possibility of mitigating eutrophication of a lagoon by
resuspension of sediment was tested in a three-year field experiment conducted in
2008–2009. An unreplicated before-after control-impact (BACI) study design was used to
ascertain variations in the quantity and biochemical composition of organic matter in
sediment artificially disturbed by a specially equipped boat. In October 2008, before
beginning disturbance, January 2009, half way through the disturbance period, and May
2009, at the end of disturbance, sediment was sampled in a disturbed area and an
undisturbed control area to determine chlorophyll-a (Chl-a), phaeopigments (PHAE),
proteins (PRT), carbohydrates (CHO), lipids (LIP), labile organic matter (LOM), refractory
organic matter (ROM), total organic carbon (TOC) and total nitrogen (TN). The disturbed
area, measuring 44 ha, was divided into nine subareas, eight of which were subjected to
four different frequencies of disturbance (from 2 to 5) in the period October 2008 – April
2009. Sediment was sampled in each sub-area in the three months mentioned above to
determine labile and total organic matter. The results were processed by univariate and
multivariate analysis using Primer 6.0, Permanova + and Prism 5.0 software. The findings
were as follows: (1) a large proportion of the biopolymeric carbon consisted of labile
matter throughout the lagoon; (2) higher abatement of labile organic matter was recorded
in the disturbed area; (3) a lower protein:carbohydrate ratio was found in the disturbed
than in the undisturbed area; (4) the C:N ratio of sediment was much lower in the
undisturbed area than in the disturbed area at the end of the study period; (5) sediment
and macroalgal C:N ratios did not significantly change in response to disturbance; (6)
initial accumulation of organic matter from phytoplankton was greater in the disturbed
area than the undisturbed area; (7) chlorophyll-a, phaeopigments and the pigment diversity
index did not reflect any decline in photosynthesis in the disturbed area; (8) treatment
effects increased with increasing frequency of disturbance. These findings indicate less
availability of labile organic matter and therefore lower risk of extended anoxic events
in the disturbed area and support our hypothesis that artificial disturbance of sediment
can be used to manage lagoon environments and prevent the consequences of
eutrophication
Fenomeni di erosione localizzata a valle di opere trasversali: integrazioni tra indagini di campo e di laboratorio
No full textVariations 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
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