1,721,018 research outputs found
Patterns and drivers of meiofaunal assemblages in the canyons Polcevera and Bisagno of the Ligurian Sea (NW Mediterranean Sea)
No full textMeiofaunal abundance, assemblage structure and richness of higher taxa were investigated for the first time in two submarine canyons (Polcevera and Bisagno) of the Ligurian Sea and along the adjacent open slope, in relation with the quantity and quality of sedimentary organic matter and other environmental variables, including grain size. Meiofaunal abundance and richness of higher taxa decreased with increasing water depth (from ca. 200 down to ca. 2000-m depth) in the open slope and Polcevera canyon, whereas the highest values were observed at 500 m depth in the Bisagno canyon. The comparison between canyons and the adjacent open slope, showed the lack of significant differences in meiofaunal abundance, at the same depth except for samples collected at 200 and 2000-m depth. Overall the biodiversity was higher in canyons than in the open slope. Phytopigments, utilised as a proxy of the input of primary organic matter, were up to 3 times higher in canyon than in slope sediments and, along with grain size, explained a large portion of the variability in all meiofaunal variables. Canyon and slope showed a high beta diversity (83%), mostly due to the presence of a high portion of rare taxa in the canyons. Some taxa, such as Cladocera, Cumacea, Gastrotricha, Nemertina were exclusively encountered in canyon sediments, whereas Tardigrada were encountered only in the adjacent slope. Results reported here indicated that, differences in meiofaunal assemblages between canyons and slopes are primarily driven by quantity and quality of the available food resources and by the presence of specific topographic features
La valorizzazione delle competenze nei lavoratori atipici
No full textL'esigenza di ri-leggere, sul piano teorico-metodologico, alcuni costrutti interpretativi del processo di orientamento e del bilancio di competenze non deve apparire come un mero esercizio accademico ma come un aiuto ad una nuova progettazione dei servizi, intesi sia come strutture che come linee di intervento consulenziale. Tali servizi potrebbero costituire una nuova specificità d’intervento, rivolta a tutte le tipologie di utenze, ma in modo particolare ai lavoratori atipici così da capitalizzare le esperienze lavorative effettuate e su queste ridisegnare/ridefinire un “nuovo progetto professionale”
Assessing the Environmental Status of five Sardinian black corals forests via Mesophotic Assemblages Conservation Status Index (MACS)
No full textMarine animal forests are important mesophotic habitats threatened by an increasing number of natural and human pressures. Although several international agreements aim to protect these vulnerable ecosystems, the Environmental Status of most of these benthic animal-structured habitats remains unknown. Based on ROV footage, we evaluated the Environmental Status of 5 black corals forests in the center of the Western Mediterranean Sea, through the Mesophotic Assemblages Conservation Status (MACS) Index. The MACS index combines two independent indices: the Index of Status of the benthic communities, analyzing conspicuous species diversity, basal layer and canopy composition; the Index of Impact, analyzing siltation level, canopy condition and marine litter occurrence. The five investigated sites are characterized by the presence of two Antipatharians, Antipathella subpinnata and Leiopathes glaberrima, dwelling in different environmental conditions. Four sites showed high and good values of the Index of Status, and only one site showed a moderate status. Regarding the Impact Index, four sites were classified with low values, except one showed a very low value. Overall, four black forests were classified in a Good and one in a Very High Environmental Status. Assessing the Environmental Status is the first step needed to monitor these essential habitats' health over time and improve the current frameworks for their conservation and protection, such as the Marine Strategy Framework Directive
Genetic diversity of the Ruditapes decussatus and evidence of its hybridization with the alien R. philippinarum in the Western Mediterranean Sea
Full text linkThe introduction of alien species in marine ecosystems is often driven by the increasing demand of fishery resources. This is the case of the Manila clam (R. R. philippinarum), ), imported in Europe from Japan since the 1970s, to meet the growing demand for clams that the native species, the grooved carpet shell clam ( Ruditapes decussatus), ), could not satisfy. Alien species introduction could threaten the genetic diversity and integrity of the native clam, also causing hybridization (i.e., gene flow from one species into the gene pool of another). Since R. philippinarum recently spread in a few important Mediterranean coastal areas, a combined approach based on morphological characteristics, length differences of two nuclear species-specific markers (ITS2, 5SrDNA) and the sequence of the mitochondrial gene cytochrome c oxidase subunit I (COI), was used to investigate the presence of hybrids in six Mediterranean wetlands (Sardinia, Italy). Eight individuals morphologically identified as R. decussatus were hybrids, having sequences specific to both R. decussatus and R. philippinarum in their nuclear DNA (ITS2 and 5SrDNA). Most of these individuals were found to be post-first generation (F1) hybrids indicating that F1-hybrids may be fertile. Secondly, to study the genetic diversity of R. decussatus in the Sardinian wetlands as well as in its whole distribution area, >380 new COI sequences from the eastern Atlantic Ocean and Mediterranean Sea were analysed along with those available from public databases. Mitochondrial COI data revealed variable haplotype and nucleotide diversities in different areas, which were not dependent on sample sizes. The aquaculture breeding activities and clam transplantation between different countries, along with the long pelagic larval dispersal and the commercial import of other bivalve species might have promoted gene exchange between different sites and thus higher diversity levels in a few wild populations. Our research, evaluating the genetic makeup of wild and hatchery stocks and clarifying the degree of hybridization, can contribute to develop further recommendations for conserving the genetic integrity of R. decussatus.
Exploring the use of metagenetic analyses to assess the biodiversity of marine nematodes.
No full textAlthough nematodes play an important ecological role in all major ecosystems, their diversity is still largely unknown. The gap between ‘known’ and estimated species richness may be due to the limitations of morphological identification which is difficult, laborious and requires taxonomic expertise, meaning that biodiversity of the group is typically underestimated. To better understand the relationships between biodiversity and ecosystem functioning is crucially important a full assessment of biodiversity. This is particularly important for marine species and small-sized metazoa. The advent of molecular techniques and overall the development of next generation sequencing techniques (i.e. 454 sequencing) provide new perspectives to investigate the biodiversity of nematode assemblages
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
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