1,720,992 research outputs found
Anatomy of a transgressive tidal inlet reconstructed through high-resolution seismic profiling
No full textAlthough themorphology and morphodynamics of modern tidal inlets have been analysed in a wealth of studies,
these systems can be considered representative only for highstand conditions, while little is known about the
characteristics and evolution of their transgressive counterparts. Through the analysis of high-resolution
seismo-acoustic profiles, this work investigates a rare example of a preserved filled tidal inlet formed during
the early Holocene on the continental shelf of the northern Adriatic Sea. The quantity and quality of the available
data allowed a detailed reconstruction of the morphology and internal architecture of this feature. This 1.2 kmlong,
17 m-thick channelized scour formed in a microtidal environment between 9.0 and 9.5 kyr cal BP. The
tidal prism is estimated to have been ca. 4.4 × 107m3. The internal geometry of the fillingmaterial shows no evidence
of migration of the inlet, which lasted only for a few centuries and was soon after drowned by the sea
transgression. This rapid evolution is in contrast with the millennial-scale lifespan of most of the modern
highstand lagoon systems. Thiswork provides a newoutlook on the evolution of tidal inlets during phases ofmarine
transgression and in relation to variable rates of sea-level rise. In many cases, paleo tidal inlets are the only
witnesses of the presence of transgressive barrier-lagoon systems which had been completely eroded by the
wave action after their submersion. These features represent therefore an important proxy to infer the position
of the related coastline and to constrain the past relative sea level
Bottom carbonate production in Little America Basin, Ross Sea, Antarctica
No full textLAB samples show that the living carbonate fauna (biocoenosis) is not entirely preserved in the death assemblage (taphocoenosis) of related sediments. Although several of the collected invertebrate species produce calcareous skeletal parts, only small amounts of these skeletons are preserved as bioclasts in near surface deposits. Our collections show that less stable carbonate minerals, such as coral aragonite, are lost rapidly. Where present, the resulting biogenic carbonate sediment close to the ice-shelf is a calcitic bryomol assemblage. Such assemblage is typical of polar and cool-temperate settings
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
Bathymetry of the Adriatic Sea: The legacy of the last eustatic cycle and the impact of modern sediment dispersal
No full textThe Istituto di Scienze Marine (ISMAR-CNR) has conducted several research projects on the Italian side of the Adriatic Sea over more than 15 years, collecting bathymetric, geophysical and sediment core data to perform multidisciplinary studies of modern sediment dynamics and of past environmental changes during the last eustatic cycle. A crucial step in this direction was the construction of a detailed bathymetry, a time-consuming task due to the extensive shallow water portion of the basin. Given the setting of the Adriatic Sea and the long-lasting research effort, the bathymetric map is necessarily based on heterogeneous data with uneven spatial distribution of Single-Beam echo-soundings. The main objective of this work is to illustrate the methodology applied to compile the bathymetric map of the west side of the Adriatic Sea at basin scale (1:750,000) and to describe the main morphological units that characterise the seafloor and reflect its main geological features. This bathymetry can also be used in oceanographic modelling both at regional and local scale, focussing on the interaction between bottom currents and seafloor morphology
Deep-water Corallium rubrum (L., 1758) from the Mediterranean Sea: preliminary genetic characterisation.
No full textThe precious red coral Corallium rubrum (L., 1758) lives in the Mediterranean Sea and adjacent Eastern Atlantic Ocean on subtidal hard substrates. Corallium rubrum is a long-lived gorgonian coral that has been commercially harvested since ancient times for its red axial calcitic skeleton and which, at present, is thought to be in decline because of overexploitation. The depth distribution of C. rubrum is known to range from c. 15 to 300 m. Recently, live red coral colonies have been observed in the Strait of Sicily at depths of c. 600–800 m. This record sheds new light on the ecology, biology, biogeography and dispersal mechanism of this species and calls for an evaluation of the genetic divergence occurring among highly fragmented populations. A genetic characterization of the deep-sea red coral colonies has been done to investigate biological processes affecting dispersal and population resilience, as well as to define the level of isolation/differentiation between shallow- and deep-water populations of the Mediterranean Sea. Deep-water C. rubrum colonies were collected at two sites (south of Malta and off Linosa Island) during the cruise MARCOS of the R/V Urania. Collected colonies were genotyped using a set of molecular markers differing in their level of polymorphism. Microsatellites have been confirmed to be useful markers for individual genotyping of C. rubrum colonies. ITS-1 and mtMSH sequences of deep-water red coral colonies were found to be different from those found in shallow water colonies, suggesting the possible occurrence of genetic isolation among shallow- and deep-water populations. These findings suggest that genetic diversity of red coral over its actual range of depth distribution is shaped by complex interactions among geological, historical, biological and ecological processes
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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