1,720,961 research outputs found
The use of preserved copepods in seabream aquaculture: biometric, biochemical and molecular implications.
No full textThe aim of the present study was to test the efficiency of a new technology able to produce preserved copepods to be used as a possible alternative to live preys (rotifers, Artemia nauplii and live copepods). Different feeding combinations and different preserved copepod sizes have been tested in order to verify the efficiency of this innovative larval food on a very common cultured species in the Mediterranean area: Sparus aurata. In this study, we demonstrated that during the early larval periods, a crucial role is played by prey motion and their biochemical characteristics. In fact, static live preys represent a limiting factor in larval rearing that in turn negatively affects growth and survival A 100% preserved copepod diet was not able to promote larval survival, however, a mixed diet based on live and preserved preys may be a good choice to enhance larval survival and growth in fish larvae. The technology herein developed underlines that preserved copepods can maintain their fatty acid composition and thus can be considered as a valid source of highly unsaturated fatty acids (HUFAs) in aquaculture. In fact, as already demonstrated in previous studies, HUFAs are able to positively modulate the expression of important genes involved in larval growth, lipid metabolism, food intake and stress tolerance
Preserved copepods as a new technology for the marine ornamental fish aquaculture: A feeding study
No full textThe aim of this study was to evaluate the potential use of preserved copepod as prey in Amphiprion clarkii larviculture. After hatching, A. clarkii larvae were divided in three experimental groups for feeding studies as follows: group A (control group) fed rotifers (Brachionus plicatilis) followed by Artemia nauplii; group B fed a mixed diet of rotifers-Artemia salina nauplii and preserved copepods and group C fed preserved copepods solely. In this study we observed a positive effect of feeding preserved copepods in A. clarkii larviculture as a
supplement food to the traditional diet based on rotifers and Artemia nauplii. In group B larvae, fed a combination of rotifers/Artemia and copepods, a significant increase of insulin like growth factor I and II, peroxisome proliferator activated receptor α−β and thyroid receptor α and β gene expression together with a significant decrease of myostatin gene expression was evidenced by real time PCR compared to the other experimental groups. In this same group we also observed the best results in terms of growth (total length and weight) and survival. These preserved copepods may be considered a suitable food for marine fish larvae larviculture when used as a supplement to the traditional diet based on rotifers and Artemia nauplii
The use of preserved copepods in sea bream small scale culture: biometric, biochemical and molecular implications
No full textConsidering the well-known problems arising from the use of
rotifers and Artemia as live prey in larval rearing in terms of
fatty acid deficiencies, the aim of this study was to evaluate a
partial or complete replacement of traditional live prey with
preserved copepods during the larviculture of gilthead sea
bream (Sparus aurata). Sea bream larvae were randomly
divided into 4 experimental groups in triplicates: group A
larvae (control) fed rotifers followed by Artemia nauplii;
group B fed a combined diet (50%) of rotifers–Artemia and
preserved copepods; group C fed rotifers followed by pre-
served copepods; and group D fed preserved copepods solely.
Survival and biometric data were analysed together with
major molecular biomarkers involved in growth, lipid metab-
olism and appetite. Moreover, fatty acid content of prey and
larvae was also analysed. At the end of 40 days treatment, a
stress test, on the remaining larvae, was performed to evalu-
ate the effects of different diets on stress response. Data
obtained evidenced a positive effect of cofeeding preserved
copepods during sea bream larviculture. Higher survival and
growth were achieved in group B (fed combined diet) larvae
respect to control. In addition, preserved copepods cofeeding
was able to positively modulate genes involved in fish growth,
lipid metabolism, stress response and appetite regulation
Preserved copepods as a new technology for the marine ornamental fish aquaculture. Aquaculture 308(3-4), 124-131.
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
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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