1,720,968 research outputs found
A ‘‘Traffic’’ Light approach for the assessment of the Broadtail shortfin squid Illex coindetii Verany, 1839 in the Southern Adriatic Sea (Central Mediterranean
No full textA multi-indicator system and the Traffic
Light methodology (TL) to provide the first
description of the Illex coindetii (Verany 1839)
stock in the GFCM geographical sub-area (GSA)
18 (southern Adriatic Sea; Central Mediterranean)
were applied using independent fishery
data (‘‘Mediterranean Bottom Trawl Survey’’,
‘‘Medits’’, programme, years 1996–2004). The
trajectories of nine population indicators of Frequency
of Occurrence (F), Biomass (BI), Density
(DI), Recruit Strength (RS), Spawner Strength
(SS), Mean Body Weight (MBW), Mantle Length
(ML), Mantle Length Excluding Recruits fraction
(MLER), Mean mantle Length-Females Length
at maturity ratio (MLLm), were analysed using
statistical estimators as arithmetic and geometric
mean, median, and 75th percentile. The TL
methodology was applied to analyse the resulting
multiple-indicator panel. Results describe a significant
trend of the I. coindetii stock (in number)
in the GSA 18 related to a shift within its
structure due to a greater proportion of small
specimens in the population. Factors that may be
contributing to the observed changes are sea
temperature, the reduction of possible predators,
the recovery of some prey species mostly due to
the fishing pressure occurring in the area, and the
fast growth and short life span of I. coindetii. In a
dynamic system like the Adriatic Sea, the capability
to respond quickly to the ‘‘environmental’’
or ‘‘ecosystem’’ changes seem to give I. coindetii
an advantage in competition with the long lived
finfish species. Accordingly, there is potential to
use squid population dynamics as recorders to
track environmental and ecological changes, as
well as overexploitation. The adopted methodology
drew attention to changes occurring within
the stock of I. coindetii, and could provide an
opportunity for managers to consider action at an
early stage. The multi-indicator system and the
TL methodology are illustrated as means to
follow dynamic changes within squid stock, and
to provide usef
Some information on the biology of Illex coindetii Verany, 1839 (Cephalopoda, Ommastrephidae) in the South-Western Adriatic Sea (Central Mediterraneam)
No full textDistribution, length frequency structure, sex-ratio, maturity and dorsal mantle length–total weight relationship for Illex coindetii (Verany, 1839)
were described for the first time in the South-Western Adriatic Sea (Central Mediterranean). Samples came from six experimental bottom trawl
surveys carried out within the framework of the Medits programme from 1997 to 2002. Although specimens have been collected at a wide depth
range, I. coindetii concentrates between 50 and 200 m. The population had a smaller squid size and length at first maturity with respect to other
Mediterranean and Atlantic regions, probably due to the interaction of some environmental factors (sea temperature and fishing pressure) and the
biological characteristics of the species. There was no difference in males/females ratio by year, but there was a general dominance of females over
males at larger sizes and of males over females at smaller sizes. The different proportion of juveniles and mature individuals in the catch suggested
the possibility of a prolonged spawning season with a spring spawning peak. There was a pronounced sexual dimorphism, females mature at larger
mantle length attaining larger size in respect of males. Length–weight relationship revealed a difference between sexes in maturing and mature
individuals only, with males resulting heavier and more robust than females at the same size. There were no differences in body proportions between
unsexed and immature individuals of both sexes, which were considerably slimmer than maturing and mature counterparts
Biodiversità dei fondi mobili nell’area costiera di Torre del Cerrano (Abruzzo, Italia).
No full textThe biodiversity of the soft bottom in the coastal area from the Vomano river to the Piomba river (Central Adriatic) has been studied. Three sub-areas characterized by different biodiversity levels have been found following latitudinal gradient (North to South)[...
Approccio preliminare per lo studio dello stock di vongole (Chamelea gallina, L.) antistante la Torre del Cerrano (TE), Mare Adriatico: una possibile Area Marina Protetta.
No full textThe coastal area in the Teramo province (middle Adriatic) is characterized, in productive terms, by the clams (Chamelea gallina) fishing through hydraulic dredges. In such context, the present research has the purpose to constitute an introductory scientific base of a project that could make feasible the institution of a protected marine area, defined as “TORRE DEL CERRANO”. Along 16 Km of marine coast between Vomano and Piomba rivers, samplings have been carried out to evaluate the community benthonic structure, the biometric analysis of molluscs, the clams defence mechanisms and their diseases. These assessments represent a cognitive base of environmental “well-being” through the study of the area general biodiversity and, more specifically, the clam population. About the community benthonic structure, the trend of main structural indexes (Margaleff, Shannon Weaver, Eveness and Pielou) has demonstrated a general spatial reduction in the biodiversity from North to South. The biometric analysis of molluscs has been carried out in three different points; the results have demonstrated the absence of sizes greater than 35 mm and the spatial increase of the average size from North to South. The defence mechanisms of the clams has been evaluated after thermic stress and, through immunoblotting with monoclonal antibody anti-hsp 70 bovine brain, the induction of a Heat Shock Protein (HSP) of approximately 70 Kda has been recorded in the mantle. Furthermore, the production of nitric oxide (NO) and reactive oxygen species (ROS), through nitrite and chemioluminescence assays, respectively, has been assessed in haemocytes of clams stimulated to phagocytize. The results have demonstrated a little increase of NO and an absence of ROS production in the haemocytes during phagocytosis. The histo-pathological examination, instead, has revealed in the clam samples the presence of gregarine oocysts and Rickettsiales-like organisms colonies. The obtained results are directed to set a methodological approach that, through continous monitoring, could unite different parameters to improve the clam resource in a context of environmental protection. [...
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
NUTRITIONAL AND QUALITY TRAITS OF CHAMELEA GALLINA (LINNAEUS, 1758) COLLECTED ALONG THE COASTAL AREA OF BARLETTA (ADRIATIC SEA, ITALY)
No full text- …
