1,721,010 research outputs found
UPWARDS MIGRATION OF SEISMIC FOCII - A FORERUNNER OF THE 1989 ERUPTION OF MT-ETNA (ITALY)
No full textHVSR and MASW seismic survey for characterizing the local seismic response: A case study in Catania area (Italy)
Full text linkMany recent researches show that the site seismic response is strongly influenced by stratigraphic and topographic features. Site response can reduce or amplify the earthquake induced ground motion. An integrated approach based on passive (HVSR) and active (MASW) seismic surveys, was carried out at the Garibaldi Hospital, located in Catania downtown, in order to evaluate the seismic site response. Fourteen environmental noise records, located near some previously mechanical drillings, were carried out and processed by using the Horizontal to Vertical Spectral Ratio (HVSR) technique. Successively, two MASW prospections were performed at the northern and the southern sides of the Hospital building, following the information deduced from the stratigraphic characteristics of soil drillings. The data obtained from this coupled analysis, method and the information derived by mechanical drillings previously performed, allowed us to obtain the site transfer function which can be related to the H/V average spectrum. Such integrated approach, based on passive and active seismic prospections, showed to be a reliable and quick method to obtain information for a site seismic characterization. According to Italian code a Vs30 profile was achieved and the soil type category was determined
New evidence for Late Quaternary deformation of the substratum of Mt. Etna volcano (Sicily, Italy): clues indicate active crustal doming
No full textStratigraphic and morphostructural analyses have been carried out in the Mt. Etna volcanic region (eastern Sicily) to investigate in detail the deformation events that have affected the sedimentary successions forming the substratum of the volcano. In the foredeep, Quaternary submarine sedimentation ended 600 ka ago when the whole area emerged in response to homogeneous regional uplift. The irregular distribution of a stratigraphic marker, recognized through the analysis of more than 250 borehole logs, suggests that local dynamics also affected the area. We identify both compressional tectonic dynamics and volcano-related tectonic activity, and discriminate among their associated deformations. In particular, we quantify the vertical deformation component of the compressional structures (thrusts and related folds) and recognize for the first time a vertical component of deformation whose pattern clearly indicates a doming process acting at Mt. Etna. The comparison between long-term and short-term rates suggests that the doming has acted consistently over space and time through the last 600 ka and provides clues to the source of uplift. This component, defined by a specific Quaternary sedimentary horizon, has been compared with vertical deformation obtained by analytical inversion of morphological substratum data, and localizes the source at a depth of similar to 16 km, at the mantle-crust transition. This uplift may be the consequence of hydration occurring in the altered ocean-like crust
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
Correlazioni tra le velocità ultrasoniche e le caratteristiche petrografiche in ceramiche archeologiche: un primo approccio metodologico
Full text linkL’analisi delle velocità degli ultrasuoni permette di investigare i caratteri tessiturali e strutturali e di individuare la presenza di eventuali difetti localizzati all’interno del campione. La loro diffusione negli studi archeometrici è legata alla non distruttività e alla possibilità di fornire risultati accurati in tempo reale. In questo lavoro sono state effettuate numerose analisi petrografiche in sezione sottile e misure di velocità di propagazione degli ultrasuoni su reperti ceramici di interesse archeologico. In particolare sono stati selezionati ed analizzati ceramiche preistoriche ed anfore da trasporto del V-IV sec. a.C., caratterizzati da differente granulometria, composizione e struttura.
Da questo primo approccio è stato possibile evidenziare che il parametro petrografico che influenza maggiormente la velocità degli ultrasuoni è la forma e la disposizione spaziale dei pori, e la dimensione media degli inclusi, mentre correlazioni poco significative si ottengono prendendo in considerazione la percentuale e il tipo di inerte presente nell’impasto ceramico
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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