1,720,958 research outputs found
Različit, ali isti: uz pomoć DNA identifikacije otkrivena iznenađujuća obojenost primjeraka Sredozemnog morskog puža stražnjoškržnjaka (Mollusca: Nudibranchia)
Full text linkA peculiar eolid nudibranch showing an unknown chromatic array was found in a rocky bottom of Santa Maria al Bagno, in the Salento peninsula, Ionian Sea (Central Mediterranean Sea). This specimen, initially identified as Piseinotecus sp., was observed in situ and photographed while feeding and laying eggs close to individuals belonging to the Mediterranean Piseinotecus soussi. To assess the identity of this unexpected Piseinotecus ‘white morph’, a DNA identification approach was carried out using mitochondrial cytochrome c oxidase subunit I (COI), as it is the molecular marker mostly used to distinguish nudibranchs species. The molecular analysis unambiguously identified this specimen as Piseinotecus soussi and helped to shed lights on the striking intraspecific colour variability characterizing this rare species.Neobični primjerak eolidnog morskog puža stražnjoškržnjaka s dosad nezabilježenim obojenjem pronađen je na stjenovitom dnu lokaliteta Santa Maria al Bagno na poluotoku Salentu u Jonskom moru (središnje Sredozemno more). Ovaj primjerak, prvobitno identificiran kao Piseinotecus sp., promatran je i fotografiran dok se hranio i polagao jaja u blizini jedinki koje pripadaju sredozemnoj vrsti Piseinotecus soussi. Kako bi se otkrio identitet ovog neobičnog „bijelog oblika“ Piseinotecus sp. primjerka, provedena je identifikacija DNA pomoću mitohondrijske podjedinice citokrom c oksidaze I (COI), budući da je to molekularni marker koji se uglavnom koristi za razlikovanje vrsta stražnjoškržnjaka. Molekularna analiza nedvojbeno je identificirala ovaj primjerak kao Piseinotecus soussi i pomogla da se rasvijetli upečatljiva intraspecifična varijabilnost obojenja koja karakterizira ovu rijetku vrstu
Sediment and bottom water eDNA metabarcoding to support coastal management
Full text linkOcean sprawl and climate change exacerbate coastal erosion and flooding, resulting in habitat loss and decreasing biodiversity. To counteract these threats, different coastal defence tools have been developed, with an increasing emphasis on nature-based solutions. However, tracking the impacts of these interventions on marine benthic organisms requires appropriate sampling designs and timely investigation methods due to the dynamic nature of coastal environments. Environmental DNA metabarcoding is a promising, non-invasive, and quick technique to monitor community changes. Here, environmental DNA COI-based metabarcoding data from sediment and bottom water samples were used to characterize benthic communities at three sites along the Emilia-Romagna coast differing in the topology of coastal defence actions (from no defences to groynes and low-crested barriers) and to evaluate the effectiveness of the two sampling matrices in detecting local biodiversity. The findings revealed significant differences in the structure of the benthic communities depending on site, sample type (i.e., sediment versus bottom water), and their interaction. The three sites differ in abiotic characteristic affecting the community composition. Lido di Dante and Riccione showed higher species diversity due to the new type of substrata provided by the hard defence structure, while Foce del Bevano showed the presence of species typical of low impacted areas. Bottom water, hosting more traces of pelagic and nektonic species, showed significantly different species composition compared to sediment samples, suggesting the need to consider both matrices in coastal monitoring
eDNA Metabarcoding Applications Across Italian Marine Coastal Ecosystems: An Overview
Full text linkClimate emergency and other anthropogenic pressures urgently call for technological and methodological advances to enhance our ability to protect marine habitats and their ecosystem services. In recent years, environmental DNA (eDNA) metabarcoding has emerged as a powerful tool to achieve an integrative assessment of the environmental health status, through a broad, relatively rapid, and cost-effective taxonomic monitoring of biodiversity at different spatial scales. Here we provide a time-based overview of the applications of the eDNA metabarcoding methodology carried out across diverse Italian marine and coastal habitats, with an in-depth scrutiny of the commonly adopted operative procedures, from sampling to sequencing. The lack of standardization and low replicability in space/time arose as major issues of several monitoring campaigns, preventing appropriate cross-comparability of previous studies. Given the wide potential of eDNA metabarcoding surveys along the Italian coastline, this review aims to boost a wider application of eDNA metabarcoding for biodiversity inventories and to avoid major methodological weaknesses that could compromise the long-term value and broad spatial scope of future monitoring plans
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
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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