1,721,145 research outputs found
Imaging the multi-level magma reservoir at Mt. Etna volcano (Italy)
Get PDFThe continuous GPS network operating on Mt. Etna with its 36 stations is currently one of the largest worldwide. The aim of this network is the evaluation of volcanic hazard and the modelling of the active sources. In this paper, we propose an in-depth analysis and modelling of continuous GPS data collected at Mt. Etna from May 2008 to December 2010. The analyzed period has been divided into four different coherent phases: 1) 14 May 2008-02 August 2008 (deflation of the entire GPS network); 2) 02 August 2008-14 June 2009 (deflation of the summit area and inflation at lower heights); 3) 14 June 2009-21 May 2010 (inflation of the entire GPS network); 4) 21 May 2010-31 December 2010 (inflation at medium and low heights and end of the inflation in the summit area). Analytical models indicate a non-uniform deformation style revealing spaced sources acting at different time on different segments of a multi-level magma reservoir. The Etnean plumbing system imaged here is depicted as an elongated magma reservoir that extends from the volcano body downwards to about 6.5 km below sea level (b.s.l.), sloping slightly towards the North-West, with storage volumes located at about 6.5, 2.0 and 0.0 km (b.s.l.). The changes in position of the modelled pressure sources during the analyzed time intervals indicate that, throughout the 2008 eruptive period, the deformation field was mostly driven by the upward migration of magma. On the other hand, the pattern of deformation recorded after the end of the eruption strongly suggests a significant contribution of the magma overpressure generated by the gas boiling, thus outlining the importance of volatiles content in magma. Citation: Aloisi, M., M. Mattia, C. Ferlito, M. Palano, V. Bruno, and F. Cannav (2011), Imaging the multi-level magma reservoir at Mt. Etna volcano (Italy), Geophys. Res. Lett., 38, L16306, doi:10.1029/2011GL048488
Sintering behaviour of a glass obtained from MSWI ash
No full textThe sintering behaviour of a glass obtained by Municipal SolidWaste Incinerator (MSWI) bottom ash (WG) was investigated and compared
with a Na2O–MgO–CaO–SiO2 composition (CG). The sintering activation energy, Esin , and the energy of viscous flow, E, were evaluated
by dilatomeric measurements at different heating rates. The formation of crystalline phases was evaluated by Differential Thermal Analysis
(DTA) and X-Ray Diffraction (XRD), and observed by Scanning Electron Microscopy (SEM) and Transition Electron Microscopy (TEM).
In CG, the sintering started at ≈1013 dPa s viscosity and Esin (245 kJ/mol) remains constant in the measured range of shrinkage, up to 9%.
In WG the densification started at ≈1011 dPa s, Esin resulted to be 395 kJ/mol up to 5% shrinkage, 420 kJ/mol at 8% and 485 kJ/mol at 10%
shrinkage. The sintering rate decreased due to the beginning of the pyroxene formation and the densification stopped in the temperature range
1073–1123K after formation of 5 ± 3% and 13 ± 3% crystal phase, at 5 and 20 K/min, respectively. Higher densification and improved
mechanical properties were obtained by applying the fast heating rate, i.e. 20 K/min
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Silica Nanoparticles and Ozone: an evaluation of in vitro cytotoxicity and genotoxicity in a model of indoor air exposition
No full textSeveral studies point out on effects of indoor pollutants (silica particles, Pb, Ni, Zn, Si, ozone,
carbon monoxide and nitrogen oxides). The work aim is a multidisciplinary study of silica ultrafine
particles (<2.5μ) in the presence or not of ozone O3 and their potential cyto-genotoxicity evaluated by
MTS, Micronucleus and Comet test in two cell lines. We analyzed A549 (adenocarcinoma human alveolar
basal epithelial cells) and HS 27(normal human fibroblasts) exposed under dynamic conditions by a
simulator IRC under stream of ozone (120 ppb) and silica particles (40μg/h). A549 cells viability at 48
hours and 72 hours exposition to silica alone or silica plus ozone doesn’t differ in respect to the control.
The viability trend in the Hs27 cells did not show any significant changes in treated samples compared to
the control in all conditions. The micronucleus and the comet tests, showed in both the cell types exposed
to silica alone or plus ozone, a significant increase in the number of micronuclei and in the tail DNA % in
respect to the control even if at different times/cell type. We found that silica alone or plus O3 provokes
genotoxic effects more evident in A549 cancer cells than in normal fibroblasts Hs27 ones.
Final output will be to obtain a picture of the role of silica particles/ozone in the indoor air quality
taking account of the potential simultaneous co-toxicant action
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
High rate GPS data on active volcanoes: an application to the 2005-2006 Mt. Augustine (Alaska, USA) eruption
Get PDFVolcanic eruptions are usually preceded by measurable signals of growing unrest, the most evident of which are the increase in seismicity and ground deformation. It is also important to identify precursors of a possible renewal of the volcanic activity and to distinguish between an eruptive activity characterized by an intrusion (with the related destructive power) and a migration of magma stored in the main conduits. The 2005-2006 eruption at Mt. Augustine (Alaska, USA) is a good example of a massive migration of magmatic fluids from depth (about 1 km b.s.l.) under the effect of gas overpressure. The movements, recorded by High Rate GPS (HRGPS) data (15 s of sampling and processing rate) from the stations deployed on the volcano, define the dimensions and the characteristics of the shallow plumbing system. In this study, we propose a model of the different stages preceding the effusive phase (the 'precursory phase'), where gas overpressure in the body of the volcano opens the terminal conduit
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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