1,720,959 research outputs found
Il ruolo del fluoro nella genesi di alcuni sinkholes dell’Italia Centrale. Stato dell’arte sullo studio dei fenomeni di sinkholes e ruolo delle amministrazioni statali e locali nel governo del territorio
No full textNel Lazio sono presenti molti depositi fluoritiferi, alcuni dei quali sono stati oggetto di coltivazione fino a tempi recenti. Si è calcolato (Locardi-Orsini, 1990) che l’intera provincia fluoritifera laziale contiene risorse dell’ordine dei 100 milioni di tonnellate, di cui la metà è costituita da CaF2 (fluorite). Diverse sono le ipotesi per la genesi ma tutte giustificano la presenza di F in associazione alla risalita di fluidi idrotermali lungo fratture connesse alle fasi finali del vulcanismo alcalino-potassico del Lazio.Ne consegue che la presenza dei depositi fluoritiferi in superficie deve essere posta in relazione alla presenza di profonde fratture regionali in grado di connettere l’area di residenza dei corpi magmatici con la superficie. Quindi l’esatta localizzazione dei siti fluoritiferi e delle aree con anomalia in F nei diversi litotipi potrebbero dare utili indicazioni sulla localizzazione dei principali sistemi tettonici regionali attivi durante gli ultimi 600.000 anni.Scopo del lavoro è quello di relazionare la localizzazione delle aree con anomalie in F, in ambiente vulcanico, con la tettonica regionale. Tali anomalie sono state ricostruite tramite analisi su litotipi ed acque. L’area in esame è il complesso vulcanico Sabatino, sede di diversi depositi fluoritiferi, di aree con anomale concentrazioni di F nelle acque e presenza di un acquifero, sia superficiale, a livello delle vulcaniti, sia profondo, di influenza regionale e impostato all’interno del basamento carbonatico. Lo studio ha previsto l’analisi di terreno circa l’ubicazione dei depositi fluoritiferi, aree di alterazione e analisi dell’assetto geologico-strutturale a carattere regionale dell’intera area sabatina. Lo studio è stato completato dall’analisi del contenuto in fluoro in acque e in campioni di sedimenti. I risultati delle analisi di terreno e di laboratorio sono state integrate in ambiete GIS con lo scopo di mettere in evidenza la distribuzione areale del fluoro I risultati delle analisi ottenuti sono stati integrati con misure del flusso di CO2 nelle aree di studio al fine di stabilire eventuali correlazioni tra la distribuzione del fluoro e l’emissione attuale di anidride carbonica, cercando ulteriori prove sulla validità del fluoro come tracciante tettonico e come possibile responsabile della formazione dei sinkholes
Comparison of methods for implementing high-resolution digital terrain models for reproducing the surface of glaciers.
No full textThe aim of the research is the tri-dimensional reconstruction of glacial topographic surfaces by the comparison of satellite images and traditional techniques, such as aerial photo images and topographic maps. The considered area La Mare Glacier (TN) East Alpes Italy, located in the Stelvio National Park, one of the Italian biggest national park. The double aim of the project is to validate and improve the techniques for the extraction of Digital Terrain Model (DTM) with a high morphologic complexity areas and to produce a DTM for studying, monitoring and quantifying the glacial resources. The DTM extracted from different sources will be integrated with GIS. Considering all the multi-disciplinary information that has been collected until now on this glacial areas, GIS represents the reference system for the analysis of the landscape changes
Automated DEM Extraction and Orthoimage Generation from EROS-A1 satellite images of Mt. Etna. Italy
No full textWe present a tri-dimensional reconstruction of the summit area of Mount Etna volcano using remote sensed images. The recent eruptions at Mt. Etna have drastically changed the morphology of the summit area. Thanks to Eros A1 satellite stereo images availability, we performed a DGPS survey for the collection of GPC (ground control point) useful to detect new topographic features necessary for the 3D model generation. Two types of GCP were collected: the first type were marked on new topographic features using reflectors visible from high resolution satellite camera (2 m x 2 m), the second type were collected using existing visible objects. The placement and marking of new reflectors have been necessary because the upper part of the volcano lacks of enough referenced features. We have therefore devised and placed a grid of new reflectors taking into account the slope characteristics of the volcano, in terms of elevation and visibility. The aim of the project is to validate and improve the techniques for the extraction of Digital Elevation Models (DEM) in areas charaterised by high morphologic complexity and to produce a DEM of Mt Etna for studying, monitoring and quantifying the volcanic changes. The extracted DEM has been quantitatively analysed in a GIS environment to obtain the up-to-date morphometry of the volcano
Metodologie a confronto per la realizzazione di High Resolution DEMs per la ricostruzione delle superfici glaciali
No full textVengono illustrate le metodologie utilizzate per la realizzazione di DEM ad alta risoluzione nella ricostruzione delle superfici glaciali
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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