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Aspects of reproduction and biochemical metabolism in Chamelea gallina from the North Adriatic Sea
No full textThe Venus clam Chamelea gallina is an infaunal filter-feeder, widely distributed throughout the
Adriatic Sea, where it has great economic importance. In the present study, some aspects of the
biological cycle of C. gallina have been investigated by evaluating the time-course of gonad
maturation and variation in gross biochemical composition and energy values. Specimens with
homogeneous size (length range 25-35 mm) were collected monthly from January to December 2001
for biochemical measurements (protein, lipid, total carbohydrate and glycogen contents and energy
values) and from November 2001 to November 2002 for the study of the gametogenetic cycle,
performed by microscopic observations of histological sections of gonadic tissue.
Protein content varied narrowly and irregularly, whereas lipids remarkably increased from April to
June 2001. Total carbohydrates and glycogen exhibited a similar erratic trend, and various relative
maxima and minima were recorded. Total energy content, evaluated by converting carbohydrate, lipid
and protein values into calorie contents, was especially stable all through the year, ranging from the
maximum of 13.2 kJ/g in September to the minimum of 10.7 kJ/g in December. Histological
observations indicated that gametogenesis started in September and kept on throughout winter until
late spring. Ripe gonads were first observed in February, and the highest percentage of ripe individuals
was detected in May, when also spawned clams were found. Spawning appeared to persist during
warm months up to July, and the maximum number of spawned clams was recorded in June. The
gonadic index was pretty suitable as a proxy for the reproductive status of the natural population: in
particular, it showed an increasing trend from January, peaked in May, decreased sharply to the
minimum value of August, (when most animals resulted sexually inactive from the histological
observations) and started rising from September-October, highlighting the gradual onset of
gametogenesis (as observed in the histological sections).
An inverse relationship was established between the gonadic index and glycogen content, particularly
between the lowest levels of glycogen and the time-span of sexual maturity and gamete emission. The
good correlation between gametogenesis and depletion of energetic reserves have been already
documented in various bivalve species (Mytilus edulis, M. galloprovincialis, Ruditapes philippinarum,
R. decussatus). However, our results did not evidence the conversion from glycogen to lipids, already
observed in the clam R. philippinarum as well as in other bivalve species, as only a slight increase of
lipid content was detected during the period of gamete maturation. As a consequence, glycogen is
indicated as the most important component in the metabolic energy storage for C. gallina
Effects of diet and density on growth, survival and gametogenesis of Hediste diversicolor (O.F. Müller, 1776) (Nereididae, Polychaeta)
No full textThe effects of diet and density on growth, survival and gametogenesis of the common ragworm Hediste diversicolor (Nereididae, Polychaeta) were investigated with the aim of contributing to define their optimal ranges in the context of a commercial farming system. Two different experimental trials were set up: in the first one, juveniles of H. diversicolor, obtained from laboratory cultures established with specimens taken from the Venice Lagoon, were fed according to three different food regimes (two based on commercial feeds and one consisting of an homogenate of the brown alga Sargassum muticum); in the second trial the juveniles were maintained at different rearing densities (300, 1000 and 3000 ind. m−2). In both trials, the effects on growth, survival and gametogenesis were evaluated at various time-intervals during the eight-week period of the experiments. Results showed that H. diversicolor might be a promising species to be commercially exploited in an indoor farming system. In particular, high-protein diets permits elevated growth rates, earlier gametogenesis and sexual maturation. Both growth and survival rates were higher at the lowest densities, whereas the processes of gametogenesis and sexual maturation were not influenced by density
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
Biochemical and histochemical responses to environmental contaminants in clam, Tapes philippinarum, transplanted to different polluted areas of Venice Lagoon, Italy
No full textkoamabayili/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
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