1,720,956 research outputs found
I Foraminiferi: incredibile fonte di informazioni sul passato e sul presente del nostro pianeta
No full textI Foraminiferi Sono organismi molto semplici, ma straordinariamente
affascinanti, che appartengono alla
classe dei Foraminiferi, regno dei Protisti. Nonostante
la ricchissima letteratura che li riguarda,
di tipo sia biologico che paleontologico, ancora
oggi presentano aspetti non completamente
conosciuti. Nel testo si offre una rassegna di alcune particolarità di questi organismi e dell'utilità della loro conoscenza
Chronostratigraphic revision of some Pliocene basins in Tuscany at the Zanclean/Piacenzian boundary
No full textThe data on Tuscan Pliocene basins (which were acquired during recent years) are revised and re-evaluated here in the light of the formal subdivision into three stages (Zanclean, Piacenzian and Gelasian) of the Pliocene Series. Particularly, data on the sediments close to the Zanclean/Piacenzian boundary are considered. These sediments registered important tectonic changes which can be accurately placed both chronostratigraphically and chronologically.
The Pliocene sedimentation in Tuscany started at the Messinian/Zanclean boundary (5.33 Ma) and ended in the uppermost Piacenzian (about 2.4 Ma). Some areas were characterised by a continuous sedimentation, while in other areas two depositional cycles were realised. in the second case the youngest sediments of the first cycle are refer-red to the Reticulofenestra pseudoumbilica LO (3.89 Ma)Globorotalia puncticulata LCO (3.59 Ma) interval, and the basal levels of the second cycle closely postdate the Globorotalia crassaformis gr. FCO (3,1 Ma). Therefore, a sedimentary hiatus of about 500 ky separates the two cycles. The end of the first cycle and the beginning of the second were caused by events which also determined sedimentary and environmental changes in the continuous succession
Calcareous plankton bio-chronostratigraphy and sedimentology of the "I Sodi" section (Siena Basin, Italy): a key section for the uppermost Neogene marine deposition in the inner northern Apennines
No full textThe “I Sodi” section is exposed in the homonymous quarry in the northern sector of the Siena Basin, one of the most extended Neogene-Quaternary post-collisional basins of the northern Apennines. The section is composed almost exclusively of marine mudstone containing a rich fossil assemblage and has been extensively investigated in past and recent times. It represents a key section to define the time interval of marine deposition in the Siena Basin and more generally in the inner northern Apennines, with important structural and stratigraphic implications. The marine infill of the Siena Basin is traditionally attributed to the Zanclean-Piacenzian (Pliocene) age. However, recently published data provided a more recent age for the “I Sodi” section (Calabrian, Lower Pleistocene) and, consequently, for the Siena Basin. This paper provides new data on this scientific debate, from sedimentological and biostratigraphical investigations. Analyses of planktonic foraminifera and calcareous nannofossils have been carried out in order to better constrain the depositional age of the section. As a result, this section is now dated more accurately to the Piacenzian.
and possibly to the lowermost Gelasian in its upper part
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
- …
