1,720,983 research outputs found
andrea-bistacchi/PZero: Pre-compiled binaries for the ProIter branch
No full textFirst release of the pre-compiled windows binaries for the ProIter branc
Association of cone sheets and radial dykes on Ascraeus Mons (Mars): structural analysis and modelling
No full textAscraeus Mons was one of the first of the Martian volcanoes to be imaged by the High Resolution Stereo Camera
(HRSC) experiment onboard the ESA Mars Express spacecraft. These images show much of the volcano at a
higher resolution than previously (12 m/px), and details of its lava flows, sinuous rilles, flank vents and tectonic
features. Concentric fractures systems (pit chains, grabens) around the volcano, changing transitionally into radial
structures systems have been recognized and cartographed using a HRSC mosaic. The structural interpretation
showed strong analogies with concentric dykes (cone sheets) on many terrestrial volcanoes such as Isla Fernandina
(Galapagos), Tejeda Complex (Canary Islands) and Cuillins Complex (Isle of Skye, Scotland). In particular this
last terrestrial analogue has been studied in detail and with the use of a Finite Element Method (FEM) modeling the
shape of the magma chamber that originated the cone sheets on the Cuillins Complex was discovered (Bistacchi
et al. 2010). An oblate inflating magma chamber is responsible for the formation of those structures. By analogy,
we tested the presence of an oblate magma chamber below Ascraeus Mons. We measured the diameter of the
transition zone between concentric and radial structures on Ascraeus Mons flanks, that is strongly related to the
diameter of the deep magma chamber (1-1.2 magma chamber diameters). With a FEM model built for Ascraeus
we have been able to discover the average depth of the oblate magma chamber, which could have originated the
concentric structures. The presence of a plume with an oblate summit instead of the magma chamber has also
been tested. Moreover an additional oblate shallow magma chamber that likely originated the summit caldera has
been verified. In addition, the deformation event that originated the structures on Ascraeus flanks has been dated
by crater counting, resulting very recent
FEM modelling and fractal analysis of concentric and radial structures on Ascraeus Mons (Mars)
No full textAscraeus Mons è l’edificio vulcanico situato più a nord nella provincia dei
Tharsis su Marte. In questo lavoro vogliamo verificare l’ipotesi che afferma
che l’ultima attività vulcano-tettonica su Ascraeus possa essere stata indotta
dalla sovrapressione di una camera magmatica di forma oblata.
Il prodotto è un campo di stress che ha causato l’apertura di fratture utili
all’iniezione di dicchi radiali e cone sheets, aventi una distribuzione simile a
quelli rinvenuti sul Cuillins Complex (isola di Skye, Scozia). In quest’ultimo
caso tramite un modello a elementi finiti (FEM) si è dimostrato che questa
particolare distribuzione di dicchi e fratture è compatibile solamente con la
presenza di una camera magmatica oblata a una data profondità. Basandoci su
un’accurata mappatura di lineamenti e strutture concentriche e radiali su
immagini HRSC (High Resolution Stereo Camera con risoluzione 12 m/pixel)
combinata con parametri fisici e reologici marziani, e soprattutto con la
posizione della zona di transizione concentrico-radiale nei sistemi di fratture
intorno al vulcano, abbiamo potuto costruire un modello FEM di Ascraeus
Mons. Si è così potuta testare la possibile presenza e profondità di una camera
magmatica oblata al momento dell’ultimo evento vulcano-tettonico (datato con
la tecnica del conteggio di crateri).
Inoltre le strutture concentriche cartografate essendo direttamente correlate
ai sistemi di fratture in profondità collegati alla sorgente magmatica e al campo
di stress, sono state analizzate secondo la loro distribuzione spaziale. Questa
distribuzione è stata descritta da una legge di potenza con esponente frattale,
che permette di ricavare la profondità della camera magmatica e confrontarla
con quella ottenuta dal modello FEM. L’incrocio e la reciproca verifica di
risultati simili ottenuti con metodi indipendenti forniscono un forte constrain sulla presenza e posizione della camera magmatica, oltre che sulla bontà dei
metodi stessi
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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