1,720,980 research outputs found
An oceanographic model of the Pelagos Area as essential tool for cetacean habitat modelling
No full textRole of wind events in the generation of (sub)mesoscale structures and their implications on the biological activity of the North West Mediterranean Sea
No full textWe study the mesoscale dynamics in the Ligurian Basin (NW Mediterranean Sea), combining the use of numerical models with satellite and in situ data. To this end, we use the Regional Ocean Modeling System (ROMS) configured at a resolution of 3 Km for a domain covering the West Mediterranean Sea. The model is forced with daily-mean boundary (oceanic) conditions extracted from MERCATOR, and with three-hourly winds, extracted from COSMO-7, models. Analysis showed the formation of intense EKE, including mesoscale eddy structures, in association with strong wind episodes. Strong eddy activities have an impact on the dynamics of the MLD, thus conditioning higher productivity episodes with periods of intense vertical mixing. Wind-induced mesoscale oceanic dynamics has also implications on the transport of pollutants and/or of suspended matter across the Basin, with impacts for the risk assessment
of adjacent coastal regions
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Identification of suitable habitats for cetaceans in the Canary Basin, NE Atlantic Ocean: evidences of hot-spots for beaked whales
No full textThe identification of suitable habitat and hotspot areas for cetaceans are increasingly urgent to inform decision makers on spatial management plans and to tackle anthropogenic threats and global changes. Little or no survey effort has been carried out so far in offshore waters of the Canary Basin (NE Atlantic Ocean) where most of protected areas are coastal or islands areas. As a consequence, there is a lack of data on distribution of many sensitive pelagic species. This is particularly the case of beaked whales. In order to fill this gap, 48 sea-surveys along fixed transects between Continental Portugal and Madeira Island were performed in 2012 and 2013, from July to October. We used GAMs to identify the role of environmental variables in shaping cetacean distribution. Then we built an Environmental Envelope model to map and predict species hotspots in the region.Results show the richness of offshore waters: in a total of 10636nm sampled, we recorded 234 sightings accounting for at least 9 cetacean species. GAM results highlight the importance of seamounts for all species, though habitat segregation occurs among groups. We recorded 28 sightings of beaked whales, all within a distance of 40nm from the base of the seamounts. Moreover, beaked whales were always sighted further than 55nm from the coast and 50% of the sightings were between 180nm to 240nm from the coast, with a median depth of about 4300m, proving the importance of sampling offshore waters. Maps produced by the Environmental Envelop model highlight that hotspots for beaked whales were also described by dynamic variables, in particular by the presence of productive mesoscale eddies.Considering ACCOBAMS priorities and EEZ extension for the area, and the urgent need for management plans, we suggest maintaining these sea-surveys to improve habitat modelling and cetacean occurrence prediction
Cetacean monitoring in Northeastern Atlantic Ocean – Occurrence and distribution for cetacean species in the Canary Basin
No full textCetaceans are ecologically important as storers and transporters of energy in marine ecosystems. They are top-down regulators maintaining the prey-predator balance in these complex and dynamic environments. Therefore, the understanding of cetacean distribution and habitat preferences represents a priority issue in marine conservation being an important support for management plans. In the Atlantic Ocean there are, at least, 30 cetacean species, but their distribution is poorly understood. Data come from few regional ‘hot-spots’ (e.g. Azores and Madeira), where research effort limits data collection to a few miles from the coast. Therefore, the knowledge about cetacean distribution in the Atlantic has to be considered very localized and not representative of the overall Northeastern Atlantic area. Cargo ships from Transinsular Company were used as Observation Platforms of Opportunity, specifically the routes from Continental Portugal (Lisbon and Oporto) to Madeira Island (Caniçal) and vice-versa, to collect data on cetacean occurrence, from July to October, 2012. A total of 113 sightings were recorded, with an encounter rate (ER) of 0.0220 sightings/nautical mile (NM) on 5136 NM on effort. A total of 7 species were identified: Tursiops truncatus, Delphinus delphis, Balaenoptera acutorostrata, Ziphius cavirostris, Physeter catodon, Stenella frontalis and Globicephala macrorhynchus. The most spotted specie was Tursiops truncatus with 21% and an ER of 0.0047 sightings/NM. Dolphins had the highest ER (0.0136 sightings/NM) representing 62% of the sightings, followed by toothed whales with an ER of 0.0039 sightings/NM and 18% of the sightings and baleen whales (Minke whales and 3 sightings of Balaenoptera sp.) with an ER of 0.0035 sightings/NM and 16% of the sightings. There were 5 sightings of non-identified cetaceans. Cetacean monitoring can act as a strong tool and support for conservation plans. Therefore, maintaining these monitoring surveys can improve the knowledge on cetacean presence and distribution in the NE Atlantic Ocean
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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
- …
