1,720,987 research outputs found
Mineralogy and petrology of the Polino monticellite calciocarbonatite (Central Italy)
No full textTwo small diatremes, about 0.25 my old, cut through Liassic limestones about 1 km NNE of the village of Polino (Long. 12°50'54′′E-Lat. 42°35'34′′N; Central Italy). The material filling the larger diatreme is mainly composed of a tuffisite with abundant lapilli showing concentric structure. Both unaltered country-rocks and massive hypabyssal carbonatite occur in the tuffisite as angular clasts and blocks, from a few mm up to more than 1 m in diameter. The Polino rock occurs in a strongly-potassic igneous district (Umbria Latium Ultra-alkaline District) which comprises phonolitic pyroclastic rocks and very rare kamafugitic lavas. Massive carbonatite blocks have an average mode of 53% Sr-Ba-rich calcite, 23% Fe-monticellite, 9% Th-perovskite plus Ti-magnetite, 6% Cr-phlogopite, 6% forsteritic olivine, about 2% Zr-schorlomite and ca. 1% Si-CO-OH apatite. Perovskite, schorlom ite, and apatite form cognate phases, whereas olivine and phlogopite, often replaced by monticellite, occur as nodules and as discrete grains with compositions and deformation features typical of mantle xenocrysts found in alkali basalts and ultramafic rocks. High modal content of Ca-carbonate, high Sr, Ba and LREE contents of calcite, the presence of rare minerals peculiar to carbonatitic rocks and an essential amount of monticellite indicate classification of the Polino rock as a monticellite calciocarbonatite.
The Polino rock represents a carbonatitic melt strongly contaminated by mantle-crystal debris. It displays unusual geochemical features having trace elements closer to those of the regional-associated kamafugitic rocks rather than to those of common carbonatites
Caratteristiche identificative di una roccia carbonatitica del Pleistocene Superiore affiorante presso Polino (Tr - Umbria).
No full textMelilitite-carbonatite association in the Umbria-Latium Ultra-alkaline District (ULUD): first recorded occurence in Italy.
No full textThe importance of microRNAs in RAS oncogenic activation in human cancer
No full textmicroRNAs (miRNAs) regulate gene expression by modulating the translation of protein-coding RNAs. Their aberrant expression is involved in various human diseases, including cancer. Here, we summarize the experimental pieces of evidence that proved how dysregulated miRNA expression can lead to RAS (HRAS, KRAS, or NRAS) activation irrespective of their oncogenic mutations. These findings revealed relevant pathogenic mechanisms as well as mechanisms of resistance to target therapies. Based on this knowledge, potential approaches for the control of RAS oncogenic activation can be envisioned
Utilizzo del GIS partecipativo pubblico finalizzato alla riduzione dell’inquinamento da nitrati di origine agricola nella collina marchigiana
No full textUtilizzo del GIS partecipativo pubblico finalizzato alla riduzione dell’inquinamento da nitrati di origine agricola nella collina Marchigiana
No full text-XXXV Convegno della Società Italiana di Agronomia
-a cura di Mori M. e Fagnano
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
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