1,721,046 research outputs found
Le aree di nursery nel contesto degli ecosistemi marini: aspetti funzionali, metodi di studio e prospettive gestionali
No full textIn questo studio si sintetizzano i principali aspetti scientifici inerenti l'identificazione e valutazione del ruolo svolto dalle aree di reclutamento per la produttività delle popolazioni ittiche. Vengono presentati e discussi i risultati di diversi casi di studio con l'obiettivo di definire un framework metodologico applicabile in Mediterraneo
Allosquilla africana (Manning) (Crustacea, Stomatopoda), a new record from southern Tuscan Archipelago (western Mediterranean)
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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
Morphometric aspects of Medorippe lanata (L., 1767) (Brachyura Dorippidae) in the Eastern Ligurian Sea
No full textBiological aspects of Medorippe lanata (L., 1767) (Brachyura Dorippidae) from the eastern Ligurian Sea (western Mediterranean)
No full textThe aim of the present study is to investigate the demographic structure and to identify some aspects of the
biology of an exploited population of Medorippe lanata (Brachyura: Dorippidae) in the eastern Ligurian
Sea, western Mediterranean. 1364 specimens (639 males and 725 females) of M. lanata were collected on a
monthly basis from January to December 2001, in a wide area of the eastern Ligurian Sea usually exploited
by the Viareggio ‘rapido’ trawl fleet. M. lanata represented an important fraction of the discard, both in
weight and in number of individuals. Maximum abundance of this species occurred in late summer-early
autumn (up to 3369 ind. km)2 and 50.6 kg km)2 in August). The overall females:males sex-ratio was
1.13:1, while the monthly sex-ratio did not differ statistically from 1:1 in all months, except in September
and October, when females significantly outnumbered males. The sampled population was composed of
two cohorts from November to April. Sizes ranged from 10 to 29 mm carapace length (CL) for females and
from 9 to 29 mm CL for males. The von Bertalanffy growth curve, computed for both sexes, gave a higher
growth rate in males than in females. Recently moulted males and females were observed throughout the
year, except in summer, when the highest number of ovigerous females was present. Females with external
eggs were collected from March to November, with peaks in August and September. The monthly evolution
of the ovarian maturity stages showed no clear temporal trend. At 21 mm CL, 50% of females were
ovigerous or showed macroscopically mature ovaries. According to the dimorphism in chelae size, the
presence of adult males (post-puberty stage) was observed all year round, from 18 to 29 mm CL, without
evident temporal trends
Modelling recruitment dynamics of hake, Merluccius merluccius, in the central Mediterranean in relation to key environmental variables
No full textHake recruitment has been examined in relation to environmental variables in two of the main reproductive areas of the central Mediterranean, the northern and central Tyrrhenian Sea. Seventeen years time series data from trawl surveys revealed high fluctuations in recruit abundance that could not be just explained by spawning biomass estimations. Generalized additive models were developed to investigate hake recruitment dynamics in the Tyrrhenian Sea in relation to spawner abundance and selected key oceanographic variables. Environmental data were explored in attempt to explain survival processes that could affect early life history stages of hake and that accounted for high fluctuations in its recruitment. Thermal anomalies in summer, characterised by high peaks in water temperature, revealed a negative effect on the abundance of recruits in autumn, probably due to a reduction in hake egg and larval survival rates. In the northern Tyrrhenian, recruitment was reduced when elevated sea-surface temperatures were coupled with lower levels of water circulation. Enhanced spring primary production, related to late winter low temperatures could affect water mass productivity in the following months, thus influencing spring recruitment. In the central Tyrrhenian a dome-shaped relationship between wind mixing in early spring and recruitment could be interpreted as an "optimal environmental window" in which intermediate water mixing level played a positive role in phytoplankton displacement, larval feeding rate and appropriate larval drift. Results are discussed in relation to the decline in hake stock biomass and within the present climate change and global warming context
Aspetti bio-ecologici di Munida intermedia (Crustacea, Decapoda, Anomura) nell’Arcipelago Toscano meridionale (Tirreno settentrionale)
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