1,720,965 research outputs found
The geodynamic evolution of the Italian South Alpine basement from the Ediacaran to the Carboniferous: Was the South Alpine terrane part of the peri-Gondwana arc-forming terranes?
No full textZircon U-Pb LA-ICPMS ages were obtained from three metasedimentary and two metavolcanic samples from the Monte Cavallino (South Tyrol) and the Cima Vallona (Carnic Alps) tectono-metamorphic groups from the eastern South Alpine crystalline basement in NE Italy. These analyses were performed to constrain the maximum depositional ages of the South Alpine domain, and to compare the spatial and temporal provenance variations with those of adjacent terranes. The detrital zircon dataset from the metasedimentary rocks (416 grains) yield populations with age peaks at 2.7–2.9 Ga, 1.8–2.1 Ga, 1.2–0.85 Ga, and 0.65–0.45 Ga, with maximum depositional ages ranging from the latest Neoproterozoic to the Silurian. The metavolcanic zircon dataset (209 grains) documents the presence of a two Ordovician volcanic events in the South Alpine domain. The detrital zircon dataset implies that the clastic units of the South Alpine crystalline basement were (a) deposited on the peri-Gondwanan active continental margin and (b) were originally sourced from the Proterozoic and Paleozoic units of NW Gondwana and hence should no longer be considered as exotic elements. The age spectra of the three metasedimentary units highlight differences between the Ediacaran basement gneiss, the Ordovician greywacke, and the Silurian metaconglomerate, suggesting up-section age variations due to a temporal change in provenance. Collectively, these new detrital zircon U-Pb ages imply that the clastic units within the South Alpine domain recorded sedimentation at c. 550 Ma on the peri-Gondwanan active continental margin, followed by rift-related continental and marine sedimentation in a back-arc basin setting until at least the Silurian. The South Alpine domain ultimately rifted off from Gondwana due to back-arc spreading, and subsequently underwent Variscan metamorphism during accretion onto the Laurussia margin, which started at c. 380 Ma and lasted until at least c. 320 Ma
Analisi delle caratteristiche in risonanza magnetica di 12 casi di patologie intracraniche non neoplastiche con diagnosi istologica nel cane e confronto con la letteratura
No full textSebbene la risonanza magnetica (RM) permetta
di ottenere immagini delle strutture cerebrali
con un buon dettaglio anatomico e rappresenti
il gold standard per l’identificazione di patologie
del sistema nervoso centrale (SNC), non
esistono caratteristiche specifiche di imaging
che permettano di giungere ad una diagnosi definitiva
in assenza di un esame istologico. Con
lo scopo di analizzare le varie espressioni patologiche
in campo neuro-radiologico veterinario
sono stati presi in considerazione 12 cani con
patologie intracraniche non neoplastiche diagnosticate
istologicamente, con l’obiettivo di
descriverne le caratteristiche di RM e di confrontarle
con quanto riportato nella letteratura
di referenza internazionale pubblicata nel periodo
1995-2012
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
Analisi delle caratteristiche in risonanza magnetica di 35 neoplasie intracraniche del cane confermate istologicamente e confronto con la letteratura
No full textIn medicina veterinaria il ricorso alla diagnostica
per immagini mediante risonanza magnetica
(RM) sta conoscendo una sempre più ampia
diffusione; pertanto, nell’ottica di un miglioramento
delle possibilità diagnostiche, terapeutiche
e prognostiche, diviene necessità sempre
più impellente la standardizzazione dei reperti
di diagnostica per immagini in relazione alla
conferma istologica. In questo studio le caratteristiche
RM di 35 neoplasie intracraniche del
cane confermate istologicamente sono state
confrontate con quelle riportate nella letteratura
scientifica internazionale pubblicata tra il
1995 e il 2012. L’obiettivo principale di questo
confronto è quindi quello di ampliare le conoscenze
sulle possibili espressioni patologiche
delle neoplasie analizzate. La peculiare casistica
presentata rende possibile, inoltre, fornire
dati originali su alcuni tipi di patologie tumorali
poco frequenti e poco descritte in medicina
veterinari
Analisi delle caratteristiche in risonanza magnetica di 12 casi di patologie intracraniche non neoplastiche con diagnosi istologica nel cane e confronto con la letteratura.
No full textAppropriate 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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