1,720,995 research outputs found
Grazing effect of two Gibbula species (Mollusca, Archaeogastropoda) on the epiphytic community of Posidonia oceanica leaves
No full textThe use of lepidochronology as a tool of analysis of dynamic features of the seagrass Posidonia oceanica of the Adriatic Sea
No full textBiological succession on silicone fouling-release surfaces: long-term exposure tests in the harbour of Ischia, Italy
No full textA static test site was set up in the Harbour of Ischia (Gulf of Naples, Italy) to investigate the antifouling effectiveness of newly developed non-polluting coatings. Two-year exposure experiments were performed on sets of panels coated with silicone-based coatings, and results were compared both to sets of panels coated with toxic agents, and non-toxic epoxydic compounds. Abiotic factors, strength of adhesion of the temporal dynamics of succession of foulers were analyzed throughout the period of immersion. Brown algae constantly represented the "border point" between the early community, dominated by slime, micro- and macroalgae, and the late community, mainly represented by bryozoans and molluscs, as well as polychaetes, sponges and tunicates. Brown algae, such as Ectocarpus siliculosus tunicates (mainly Botryllus schlosseri) and polychaetes (Hydroides elegans, Pileolaria pseudomilitaris) were demonstrated to be key species, triggering the community and influencing its development. Light was the main abiotic factor discriminating the community on the two sides of panels exposed to different irradiances. The best performing coatings (silicone easy release coatings without additives) substantially influenced community structure, shifting it to the earliest stages of colonization. Silicone coatings proved to be unsuitable for colonization by organisms typical of mature communities, due to their low energy surfaces. The results of the present paper demonstrate that silicone coatings technology represents an alternative to the use of biocidal antifouling paints
Distribution of benthic phyto and zoocoenoses along a light gradient in a superficial marine cave.
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Temporal dynamics and biomass partitioning in three Adriatic seagrass species: Posidonia oceanica, Cymodocea nodosa, Zostera marina
No full textGoing 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
Marine taxa of Cocconeis on leaves of Posidonia oceanica, including a new species and two new varieties
No full textEight Cocconeis Ehrenberg taxa (species and varieties) epiphytic on the leaves of Posidonia oceanica (L.) Delile were studied by scanning and transmission electron microscopy. Samples of Posidonia oceanica were collected throughout the year from seagrass meadows around the island of Ischia (Gulf of Naples, Italy). On the basis of some peculiar ultrastructural characteristics of the valve areolation, a new species, Cocconeis multiperforata sp. nov., and two new varieties, C. neothumensis var. marina var. nov., and C. scutellum var. posidoniae var. nov., are described. Ultrastructural analysis also revealed new morphological characteristics in C. britannica Naegeli in Kutzing and C. maxima (Grunow) Peragallo and Peragallo, and confirmed observations of other authors for C. molesta var. crucifera Grunow, C. pellucida Grunow in Rabenhorst and C. stauroneiformis (Rabenhorst) Okuno. Our observations on the abundance of the different species provide new information on their distribution and ecology
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
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