1,720,996 research outputs found
The changing biogeography of the Mediterranean Sea: from the old frontiers to the new gradients.
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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
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
Trophic Requirements of the Sea Urchin Paracentrotus lividus Varies at Different Life Stages: Comprehension of Species Ecology and Implications for Effective Feeding Formulations
Full text linkInvestigations on trophic requirements of different life cycle stages of Paracentrotus lividus
are crucial for the comprehension of species ecology and for its artificial rearing. The future
success of echinoculture depends heavily on the development of suitable and costeffective diets that are specifically designed to maximize somatic growth during the early
life stages and gonadal production in the later stages. In this context, a considerable
number of studies have recommended animal sources as supplements in sea urchin
diets. However, with the exception of Fernandez and Boudouresque (2000), no studies
have investigated the dietary requirements over the different life stages of the sea urchin. In
the present study, the growth and nutrition of three life stages of P. lividus (juveniles: 15-25
mm; subadults: 25-35 mm; adults: 45-55 mm) were analyzed over a 4-month rearing
experiment. Three experimental diets, with 0%, 20% and 40% of animal sourced
enrichments, were tested in parallel in sea urchin three size classes. The food
conversion ratio, somatic and gonadal growth were assessed in each condition in order
to evaluate the optimal level of animal-sourced supplements for each life stage. A general
growth model covering the full post-metamorphic P. lividus life cycle was defined for each
condition. During the juvenile stage P. lividus requires higher animal supply (40%), while a
feeding requirement shift takes place toward lower animal supply (20%) in sub-adult and
adult stages. Our results evidenced that the progressive increase in size after the
metamorphosis led to a consequent variation of trophic requirements and food energy
allocation in the sea urchin P. lividus. Macronutrient requirements varied widely during the different life stages, in response to changes in the energy allocation from somatic growth
to reproductive investment. This study sheds light on P. lividus trophic ecology,
broadening our basic knowledge of the dietary requirements of juveniles, sub-adults
and adults as a function of their behavior also in the natural environment
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