1,720,966 research outputs found
Preliminary ROV surveys data on deep-coral assemblages from South-East Sardinian Sea (central western Mediterranean)
No full textDeep-sea habitats have a high conservation interest since they often host greater diversity than surrounding areas as well as unique assemblages. Within a deep-sea research cruise aimed to monitor the presence of the resource from circa-littoral to down to the upper bathyal zone (from100 to 300 meters), the occurrence of the most representative coral species was observed. The cruise was carried out on board the ISPRA’s R/V Astrea in the Southeastern waters of Sardinian (Central-Western Mediterranean) during Autumn 2011 by means of Remotely Operated Vehicle (ROV Seaeye Falcon by Saab). Biological data were collected combining large and fine scale Multibeam dataset and ROV imaging. Three heads of canyons located inside the Marine Protected Area of Capo Carbonara were investigated and species belonging to three main orders (gorgonians, alcyonaceans and antipatharian) were recorded to characterize those rocky habitats. The results, in terms of occurrence and abundance of the main species are presented, considering these cnidarians as valid surrogate descriptors of megabenthic marine biodiversity due to their richness, abundance and identification easiness. Among gorgonians, few banks of both living and dead red coral were documented. Also the presence of discarded fishing gear and other kind of anthropic debris has been recorded, showing how these environments are potentially threatened by human activities. Given the rarity of fine-scale in situ direct observations, the present study aims to describe preliminary data on deep-sea corals diversity in a poorly investigated area in the heart of the Mediterranean Sea, representing an important contribution in filling the existing gaps in knowledg
A multiple models investigation on age and growth of the speckled ray (Raja polystigma) from Sardinian seas
No full textAge and growth of the small Mediterranean endemic skate, Raja polystigma Regan 1923 were studied through the annuli counts in vertebral centra. During the period between 2012 and 2013 a total of 183 speckled rays (97 females, ranging from 115 to 590 mm in TL and 87 males with TL among 118 and 521 mm) were caught through experimental (MED.I.T.S.) and commercial trawl surveys. From each individual total length (TL in mm) total mass (TM in g) in addition to the gender and maturity stage were recorded, then vertebral centra were extracted from the thoracic cavit. Annuli counts were made by two readers through the observation of vertebral sections stained in Alizarin Red. Readings showed a good reproducibility (Percent of Agreement = 86.8, %Cv = 7.0, Index of Average Percent Error = 5.177). The oldest skate observed was a female estimated at age 11 (TL = 590 mm) while the oldest male was aged 8 (TL = 521 mm). Four different models were applied on length at age data: the common von Bertalanffy growth function, the Exponential, and finally the Gompertz and the Logistic functions. According to the Akaike’s Information Criterion values the Logistic model (L∞ = 691.49 mm ± 10.21; K = 0.26 ± 0.008; point of inflection = 4.03 y-1 ± 0.147), followed by Gompertz function, provided the best fitting curve, showing a higher growth rate and consequently a lower L∞ value than what obtained with the VBGF (L∞ = 784.49 mm ± 12.2; K = 0.11 ± 0.004; t0 = -1.718). This result was obtained also for females and males separately. Given the best fitting results achieved with the Gompertz and the Logistic functions, R. polystigma seems to grow relatively faster during the first few years as previously reported for other batoid species
Artificial dens for Octopus vulgaris Cuvier, 1797 in the Sardinian Sea
No full textMonitoring on 244 artificial dens from 2011-2013 in the Sardinian Sea, showed that
Octopus vulgaris (Cephalopoda: Octopoda) chose them as shelters (40.72%), staying inside (86.67%)
or leaving only signs of its occupation (13.33%). The 58.97% of the dens with animals inside had
spawning females, with their eggs completed the embryological development. These preliminary results
suggest the use of artificial dens in fishing management to protect the octopus stock
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
koamabayili/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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