1,721,015 research outputs found
Short-term effects of enhanced zinc concentrations on population parameters of Dinophilus gyrociliatus (polychaeta)
No full textSurvival and fecundity data, recorded in experimental populations of the archiannelid polychaete Dinophilus gyrociliatus were used to investigate the life-table response to enhanced zinc concentrations. Results evidencing a decrease of net reproductive rate (Ro), stable rate of population increase (r) and reduction of generation time (T), highlight a complex effect of zinc, in which reduction of fecundity is compensated by the concomitant decrease of generation time
Recovery of the macrozoobenthic community of the Comacchio lagoon system (northern Adriatic Sea)
No full textFrom 1976 to 1992 the Comacchio lagoon system (a polyhaline lagoon on the northern Adriatic Sea coast) was exploited for intensive farming of eels and other fish. This activity, and its consequent increased release of organic matter, has led to hypereutrophication of the lagoon, resulting in a bloom of cyanobacteria and all almost total elimination of cukaryotes at both the planktonic and benthic level. After farming stopped, the ecological conditions tended to improve and the macrozoo-benthic community underwent a spectacular recovery The current communities do not differ substantially fi om those present before this ecological catastrophe, with the exception of a low level of internal differentiation not only among different lagoon sites but air, different substrates
LONG-TERM EUTROPHICATION EFFECTS ON MACROFAUNAL COMMUNITIES IN NORTHERN ADRIATIC SEA
No full textThe macrozoobenthic community in the northern Adriatic Sea, south of the Po river, along the Emilia-Romagna region coast, was sampled in 1985. Sampling site was central to a highly eutrophicated area with greatly increased intensity and frequency of dystrophic events over recent decades. The sampled community differs from all those described in the same area in a period (1934-1936) previous to the actual degree of eutrophication. Large abundances of species indicative of unstable bottoms, such as the bivalve Corbula gibba and the polychaete Lumbrineris latreilli were recorded. Moreover, the community structural features indicate a state of immaturity, such as in early successional stage communities. The increased frequency of acute dystrophic events and consequent shortening of the time between successive disturbances is proposed as the cause of biocenosis modification and its current structure and composition
Effect of submerged structures on the diversity of macrozoobenthos in the Northern Adriatic Sea.
No full textOffshore expoitation of oil and other hydrocarbons requires the installation of platforms or similar structures fixed to the sea bottom. Generally, such structures remain in situ for long time after the end of drilling and pruduction activities. The macrozoobenthic communities of a sea area located in the Northern Adriatic Sea sorrounding one of these platforms were studied on two occasions: the first prior to the installation of the platform (1985), the second 8 years later (1993), after production and other activities had terminated. On both occasions, sampling were performed according to similar sampling grids extended about 3.5. km from the platform site. Comparing the community composition of the two periods, a remarkable decrease of surface deposit-feeders was observed in the second period. Ordering techniques, applied to the entire data set of communities samples of both periods, pointed out not only the expected separation of the sampling points of the two periods but also a different patter of dispersion
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
Pulsed low power lasers and pulsed electromagnetic fields on isolated and integrated biosystems
No full textPulsed low power lasers and pulsed electromagnetic fields on isolated and integrated biosystem
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
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