1,721,010 research outputs found
Seabed classification around Lampione islet, Pelagie Islands Marine Protected Area, Sicily Channel, Mediterranean Sea.
No full textWe present the first seabed map of the shallow-water areas of Lampione, the islet of to the Pelagie Islands Marine Protected Area (Sicily Channel, Italy). The seafloor was mapped from the coast to about a depth of 75 m using high-resolution multibeam systems (both for bathymetry and backscatter) along with ground-truth data in the form of grab samples and ROV video-observations. The map was produced using Remotely Sensing Object Based Image Analysis by integrating information derived from multibeam system, validated by ground-truth data. The resulting 1: 5.000 scale map includes sediment types and habitat distribution contributing to the knowledge of the peculiar marine ecosystem observed at Lampione, that will be checked and implemented through further surveys. In particular, the map provides the first indication of the occurrence of rhodolith/maërl habitats at Lampione, which are among the most important ecosystems in the Mediterranean Sea
New bathymetry of the Linosa volcanic complex from multibeam systems (Sicily Channel, Mediterranean Sea)
No full textThis paper presents new bathymetric data acquired around Linosa Island, in the Pelagie Archipelago, revealing the submarine extension of the volcanic edifice, more wide and complex than previously known. The seafloor of Linosa, from the coastal area to about 1000 m depth, was mapped with multibeam systems during the ‘Linosa 2016’ and ‘BioGeoLin 2017’ surveys. A bathymetric map of the surveyed area (about 298 km2) was drawn at the original 1:30,000 scale. Overall, the submarine portions of Linosa extend on a total area of about 159 km2 and are preferentially developed in a NW-SE direction, in agreement with the regional main tectonic trend in the area. The new bathymetric data allow to recognize different sectors in the submarine extension of the volcanic edifice where constructional (volcanic) activity alternates with erosive-depositional processes affecting the submarine flanks of the island
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
New insights on the evolution of the Linosa volcano (Sicily Channel) from the study of its submarine portions
Full text linkLinosa Island represents the emergent tip of a mostly submarine, much wider volcanic edifice, with at least 96% of its areal extent lying below sea level. Marine geological surveys carried out in 2016 and 2017 allowed to reconstruct the submarine portions of Linosa and to characterize the main volcanic features, providing new, unexpected insights on the evolution of this little-explored volcanic complex. In particular, the submarine setting of the NW offshore is represented by a ~10-km long volcanic belt punctuated by a number of small eruptive cones, appearing more recent with respect to the assumed Mid/Late-Quaternary age of volcanism on the island. This evidence suggests that the growth of the volcanic edifice has likely been more complex than that claimed on the base of subaerial volcanism only, and supports a north-westward migration of the activity over time. The submarine southern flank of the volcanic edifice is also characterized by eccentric eruptive cones, but mostly without evidences of recent activity. The main processes responsible for the growth and evolution of Linosa volcano and their possible relative chronology are discussed in the framework of what previously known on the base of the limited subaerial portions, with implications on the potential hazard of the volcanic edifice (considered as not-active in recent times). Similarity with the Pantelleria volcano, located in the NW Sicily Channel, are also evidenced, especially for what regards the distribution and morphometric characteristics of eruptive cones occurring in the submarine portions of both islands
Present-day infralittoral prograding wedges (IPWs) in Central-Eastern Tyrrhenian Sea: Critical issues and challenges to their use as geomorphological indicators of sea level
No full textA census of 83 Infralittoral Prograding Wedges (IPWs) was carried out in the Central-Eastern Tyrrhenian Sea, to learn more about their morpho-bathymetric variability and test their reliability as environmental indicators of current sea level. With this aim, a database recording for each wedge the main morphometric indices, the effective fetch and the significant height of the storm waves– here used as proxies for sea state forcing to which they are exposed- and the ground elevation in the backshore - here used as a numerical descriptor of coastal morphology and energy of the relief- was realized (Campania Region IPWs Database).
The statistical analysis on the entire IPWs dataset explored the relationship between the environmental and morphometric variables while the Principal Component Analysis grouped the variables into two clusters, governed by sea state forcing and energy of relief in the backshore, respectively. The multi-regression analysis highlighted a significant correlation of IPWs depth with effective fetch and extreme significant wave height and a moderate correlation with the ground elevation in the backshore. The outcomes that emerged from the observational law on present-day IPWs were then applied to relict IPWs, currently lying on the continental shelf and at the shelf margin, with the aim of establishing their original depth of formation. This procedure aims to solve the non-trivial issue, namely that concerning the reliability of paleo-IPWs as proxies for past sea levels. Thus, a simplified equation based only on the use of geographical variables is proposed here to roughly establish the original depth (with errors of few metres) of paleo-IPWs, whose geographical exposure is known and the effective fetch computable. Although the applicability of this method suffers from spatial and temporal restrictions, due to the girth of the original dataset, it provides a first analytical procedure for gauging the original depth of formation of paleo-IPWs which, over the last decade, have been increasingly used as environmental indicators of past sea levels. This study highlights the relationship between the depth of these sedimentary coastal bodies and sea storm wave climate at a regional scale and provides clues for the use of their past counterparts as morphological proxies of past sea level stands. Further developments of this study would use a wider dataset so as to extend the observational law on present-day IPWs to a Mediterranean scale and strengthen the applicability of the method to a spatially broader set of paleo-IPWs
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
Spatial Distribution of Benthic Foraminifera in the Neretva Channel (Croatia Coast): Faunal Response to Environmental Parameters
Full text linkBenthic foraminiferal assemblages have been studied at 11 sediment surface samples located in the Neretva Channel covering the delta habitat and the adjacent open sea areas. The major objective of the investigation was to explore the main environmental parameters affecting the benthic foraminifera compositional changes. To this end, a statistical approach was applied that integrates micropaleontological data with physical, geochemical and sedimentological parameters (total organic carbon and grain size). Statistical analyses identified four distinct groups (cluster A1, A2, B1, B2) corresponding to different environmental settings. Cluster A1 groups samples under Neretva river influence and is characterized by Aubignyna perlucida, Nonionella turgida, Eggerelloides scaber and Rectuvigerina sp.; species able to live in organic-matter-rich sediments and in a wide range of oxygen content. Cluster A2 includes samples distant from the fluvial outlet and samples along the NW coast partially influenced by the Neretva river plume. In these environmental conditions, Ammonia beccarii, Bulimina marginata, Nonionella turgida and Textularia sp. resulted as the most characteristic taxa. Cluster B1 distinguishes the deepest stations which are in connection with the open Adriatic Sea. Here Asterigerinata mamilla, Buccella granulata, Cibicides group, Reussella spinulosa and Textularia sp. reach their maximum abundance associated with coarse-grained sediments. Cluster B2 groups samples collected in the inner bay of the southernmost sector of the studied area characterized by silt and clay and a negligible influence by river inputs. The benthic microfauna is principally composed of Miliolids, Porosononion granosum and Textularia sp
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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