1,721,006 research outputs found
IODP Exp. 381 - A new climate and sea-level record from the Corinth Rift - Ilaria Mazzini
No full textIODP Exp. 381 - A new climate and sea-level record from the Corinth Rift - Ilaria Mazzini </p
Glacial-interglacial sea level rise from ostracod assemblages (Gulf of Corinth IODP Exp 381) - Roberta Parisi, Ilaria Mazzini
No full textGlacial-interglacial sea level rise from ostracod assemblages (Gulf of Corinth IODP Exp 381) - Roberta Parisi, Ilaria Mazzini</p
A reassessment of the origin and distribution of the subterranean genus Pseudolimnocythere Klie, 1938 (Ostracoda, Loxoconchidae), with description of two new species from Italy
Full text linkGroundwater ecosystems host a rich and unique, but still largely unexplored and undescribed, biodiversity. Several lineages of ostracod crustaceans have subterranean representatives or are exclusively living in groundwaters. The stygobitic genus Pseudolimnocythere Klie, 1938 has a West Palearctic distribution, and includes few living and fossil species of marine origin. Through a comprehensive literature review and the description of the two new living species, Pseudolimnocythere abdita sp. nov. and Pseudolimnocythere sofiae sp. nov., from springs in the Northern Apennines, Italy, a morphological analysis was carried out with the aim of comparing the valve morphology of living and fossil species, and to discuss previous hypotheses about time and mode of colonization of inland waters. Pseudolimnocythere species show a low variability in valve morphology, with a remarkable stasis over geological times. The distribution of extant and fossil species is consistent with a scenario of multiple and independent events of colonization of continental habitats linked to sea level variations starting from Middle Miocene in the Paratethys and, later, in the Mediterranean. The most common colonization routes of inland waters have taken place through karst formations along ancient coastlines, although we cannot exclude some minor active migration through the hyporheic zone of streams. Available distribution data suggest a poor dispersal ability of Pseudolimnocythere species after they had colonized continental waters
The plant landscape of the imperial harbour of Rome
No full textThe research concerns the Tiber delta area, about 3 km far from the present seacoast, where the remains of the ancient harbour of Rome are located. In 42 AD, Claudius started the construction of the harbour and Nero completed it in 64 AD. Then, the emperor Trajan went on to add a hexagonal basin to the former structure, which had gradually silted up. The imperial harbour was connected to the Tiber River and ultimately to the city of Rome through the Trajan channel. During the imperial period, most of the supplies imported from the Mediterranean provinces reached the city of Rome through Portus.This study applies detailed pollen, microcharcoal, and ostracod analyses together with radiocarbon dating to the sediments recovered from two cores drilled in the area of the Claudius harbour. The objective of the drillings was to identify morphological and environmental features of the Tiber delta dating back to the Roman period, and to characterize the landscape of the harbour.The chronological framing of the records is based on stratigraphical criteria, radiocarbon dates, historical data and on the typology of pottery fragments. Pollen, plant macroremains, and ostracod assemblages indicate that the two cores record different periods of time. The dock core shows the first phases of the harbour activities, recording first a marine and then a brackish environment. The plant landscape is typical of a coastal environment and appears rather preserved. The human presence is clear, but not of great impact. The channel core records mainly a brackish water environment and a strong human impact related to the presence of Portus, the port town. Anthropic indicators such as cultivated and synanthropic taxa as well as strong fire use/occurrence are evidence of a high human pressure increasing in the first centuries AD. © 2010 Elsevier Ltd
Ostracods in archaeological sites along the Mediterranean coastlines: three case studies from the Italian peninsula
No full textAncient harbour basins, lagoons and coastal lake sediments buried beneath the
Mediterranean delta plains can be considered as long-term archives of anthropogenic impacts.
The benefits of a micropalaeontological approach in studying archaeological sites located in
marginal marine environments are that the archaeologically biased picture can be strongly enriched
by detailed palaeolandscapes information.
In marginal marine environments, ostracods are known to be excellent indicators because:
(1) many species have a well-known tolerance to salinity variations; (2) the analysis of population
structure provides good indications about the autochthony of the assemblage; and (3) they react
to even subtle environmental changes, both natural and anthropogenically forced, in terms of
densities, distribution of selected species and phenotypic traits.
Examples of ostracod studies will focus on three site typologies: buried landlocked harbours,
fluvial harbours and coastal lagoons/lakes. In those studies, the use of different but complementary
approaches (archaeology v. micropalaeontology) allowed the reconstruction of diachronic landscapes,
linking the natural evolution of coastal and alluvial plains to regional population and
settlement dynamics
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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