1,721,052 research outputs found
Periodical reactivation of slow movements due to rainfall regime in the Orvieto overconsolidated clay slope
No full textThe northern slope of the Orvieto hill (Central Italy) is affected by slow intermittent movements within the overconsolidated clays at depth and in the overlying debris cover. Inclinometer and piezometer (Casagrande) measures show that reactivations are rainfall-induced. This encourages the interest in a predictive seepage model which allows to evaluate rainfall conditions determining pore pressure threshold for reactivation. Since the low permeability of the materials raised doubts on the correlations between piezometer and rainfall data, new boreholes were instrumented with vibrating wire cells. Their time histories are compared to those of Casagrande piezometers and the applicability of the two instruments is discussed. Finally, results of a preliminary model are presented, comparing calculated and measured time series of pore pressure in the shal-lower portion of the slope
Caratteristiche di resistenza del materiale vulcanoclastico della Sciara del Fuoco (Stromboli)
No full textNella nota sono descritti i risultati di una serie di prove di laboratorio per lo studio della resistenza al taglio del materiale vulcanoclastico coinvolto negli eventi franosi che nel dicembre 2002 hanno interessato il versante della Sciara del Fuoco (Stromboli). Le prove sono state effettuate sia su materiale asciutto, rappresentativo delle condizioni del versante subaereo, sia su materiale completamente saturo, rappresentativo del pendio sommerso. In quest’ultimo caso, prove non drenate hanno messo in evidenza che si può verificare liquefazione statica anche negli orizzonti grossolani a patto che abbiano un significativo contento in fini quale quello prodotto a seguito di intense deformazioni di taglio
GPR investigations to evaluate the geometry of rock slides and buckling in a limestone formation in northern Italy
No full textGround Penetrating Radar (GPR) investigations were performed to assess the depth and geometry of rock slides and buckles affecting a dip slope of regularly stratified limestones interbedded with marly-clayey horizons in the south-eastern Alps. This method was chosen because the absence of high cuts in the rock mass and the presence of debris and loosened slabs on the slope did not allow the geometry of the sliding mass to be described solely by means of field mapping. The application of GPR was encouraged by the favourable conditions of the geological "environment". More than 23 medium-frequency GPR lines were performed over compressive and tensile structures as well as over undeformed limestone sequences. Digitally collected data were filtered and processed to enhance deeper reflections, as well as corrected to account for topographic irregularities. GPR was instrumental in assessing the depth of the deformational and failure structures (e.g., buckle folds and tension cracks) induced by the instability phenomena as well as in evaluating deformation continuity along the sliding mass. The GPR surveys confirmed that the layers are continuous over extensive areas (even at the maximum penetration depth of about 6 m) and that deformations involve layer packages which are at least 5 metres thick. The first result indicates the importance of accounting for the mechanical separation of layers when conducting stability analyses while the second points out the inadequacy of common limit-equilibrium/elastic instability analyses. In fact, this type of procedure envisages the instability of much thinner layer packages, thus suggesting that a more complex elasto-plastic deformation analysis of thicker layer packages is more suited to this kind of phenomenon
Caratteristiche dinamiche e di compressibilità di una pozzolana debolmente cementata alla scala del laboratorio
No full textEffetti dell’intrusione superficiale del magma sulla stabilità della Sciara del Fuoco (Stromboli)
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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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