1,721,017 research outputs found
Orbital tuning of a lower Cretaceous composite record (Maiolica Formation, central Italy)
Full text linkCALCAREOUS PLANKTON BIOSTRATIGRAPHY AND AGE OF THE MIDDLE MIOCENE DEPOSITS OF LONGANO FORMATION (EASTERN MATESE MOUNTAINS, SOUTHERN APENNINES)
No full textThe integrated calcareous plankton biostratigraphy (planktonic foraminifera and calcareous nannofossils) and an accurate fieldwork, allowed us the reconstruction of the sedimentary evolution of the Longano Formation (Orbulina Marls). In particular the correlation between the bioevents recognised in the Orbulina Marls sequence and those recorded in astronomically calibrated Middle Miocene sections, offered the possibility to date the passage from the shallow-water Cusano Formation to the deep-water deposits of the Longano Formation at about 13.21 Ma and the successive onset of terrigenous deposits of the Pietraroia Formation at 10.54 Ma. In addition, an high resolution study of the terrigenous sequence, showed that this sedimentary event is not abrupt but it is characterised by a progressive increase, bed by bed, of the siliciclastic fraction up to the deposition of the sandstones. The recognition in all the studied sections of the base of the first Acme (AB1) of Paragloborotalia siakensis dated at 13.21 Ma, just above the phosphate-rich interval (this interval marks the transition between Cusano and Longano Formations), proved that the transgression which led to the deposition of the Orbulina Marls was synchronous in all the south-eastern Matese Mountains
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
Metodologie di prelievo, preparazione di campioni e analisi delle associazioni a foraminiferi nei sedimenti di mare profondo: un esempio dall’Atlantico equatoriale orientale (Carota S13-33)
No full textIn questa nota sono descritte le metodologie di campionatura, di trattamento dei campioni e di analisi delle associazioni a foraminiferi dei sedimenti della carota S13-33 prelevata nell'Oceano Atlantico equatoriale orientale (coor¬dinate geografiche: Lat. 0°51'S, Long. 12°45'W; profondità -3500 m). La zona studiata si colloca su un margine di tipo trasforme, nella regione a sud della zona di frattura "Chain". Essa è interessata dalla Corrente calda Sud-Equatoriale ed è ubicata a Nord della regione caratterizzata dalla Corrente di upwelling del Benguela.Le ricerche micro¬paleontologiche sui sedimenti di questa carota sono inquadrate nell’ambito di un pro¬gramma di geologia marina nella regione atlantica suddetta, coordinato dal prof. B. D'Argenio ed inserito nel progetto multi¬disciplinare "Primar" ("Project Russian Italian Mid-Atlantic Ridge") in collaborazione tra gli Istituti di Geologia Marina del CNR di Bologna e Napoli, l'OGS di Trieste e l'Accademia Russa delle Scienze di Mosca.
Gli studi sulle associazioni a foraminiferi saranno sistematicamente integrati con le analisi degli isotopi stabili dell’ossigeno (*18O) nei gusci di specie selezionate di foraminiferi sia planctonici che bentonici e con la datazione radiometrica di alcuni livelli della carota per perseguire i seguenti obiettivi principali:
•ricostruzione stratigrafica ed evoluzione paleoclimatica durante l’intervallo temporale considerato attraverso lo studio integrato dei dati quantitativi e statistici dei foraminiferi planctonici e dei dati geochimici;
•evoluzione paleoecologica e paleoceanografica durante l’intervallo temporale considerato attraverso lo studio integrato dei dati quantitativi e statistici dei foraminiferi bentonici e planctonici e dei dati geochimici
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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