1,721,021 research outputs found
The Antarctic Seismographic Argentinean Italian Network - ASAIN Improving the instrumental coverage in Antarctica
No full textScientific investigations of the Scotia Sea region are crucial to
understand the history of the Antarctic continent tectonic evolution and the
influence of the aperture of the Drake passage in establishing the Circumpolar
Antarctic Current, as stressed by many authors (e.g. Lodolo, 2008). The Scotia
Sea occupies a roughly rectangular area of about 900.000 km . This area is
limited on three sides by the Scotia Arc, formed by islands and oceanic ridges,
which is a remnant of the mountain chain that joined the South American Andes
to the Antarctic Peninsula. The western border is represented by the about 1000
km wide Drake passage, that separates today the Tierra del Fuego in South
America from the Antarctic continent. A review of the tectonics and evolution
of the Scotia Sea can be found in Barker, 2001. The start of the geophysical
studies in this area dates back to several decades ago, but only after 1990
instrumental passive seismology started to be widely applied to investigate the
crustal properties and the properties of the seismic sources responsible for the strong
seismicity level observed along the Scotia plate boundaries. ASAIN started
operation in 1992 when a temporary seismograph was installed at the
Argentinean Base Esperanza. It grew quickly during the nineties and today five
stations are operated in Antarctica and two in Tierra del Fuego. All the Antarctic
stations transmit real-time data to the OGS and to the Instituto Antartico
Argentino. Esperanza (ESPZ), Jubany (JUBA), San Martin (SMAI) and
Orcadas(ORCD) stations also participate in the Virtual European Seismographic
Broadband Network (VEBSN) transmitting real time data to the Orfeus Data
Centre. On January 16 , 2009 BELA station was added to the network. It is
operated at the southernmost Argentinean Base Belgrano II (77° 52' S,
34° 37' W ) located on a rocky outcrop (Nunatak Bertrab) on the Filchner barrier. Its
inclusion in the VEBSN is also planned. ASAIN data real-time acquisition is
performed using SCREAM software, but also Earthworm and Antelope
software are being tested at the OGS Seismological Research Centre.UnpublishedErice (PA), Italy1.8. Osservazioni di geofisica ambientaleope
The Antarctic Seismographic Argentinean Italian Network - ASAIN Improving the instrumental coverage in Antarctica
No full textScientific investigations of the Scotia Sea region are crucial to
understand the history of the Antarctic continent tectonic evolution and the
influence of the aperture of the Drake passage in establishing the Circumpolar
Antarctic Current, as stressed by many authors (e.g. Lodolo, 2008). The Scotia
Sea occupies a roughly rectangular area of about 900.000 km . This area is
limited on three sides by the Scotia Arc, formed by islands and oceanic ridges,
which is a remnant of the mountain chain that joined the South American Andes
to the Antarctic Peninsula. The western border is represented by the about 1000
km wide Drake passage, that separates today the Tierra del Fuego in South
America from the Antarctic continent. A review of the tectonics and evolution
of the Scotia Sea can be found in Barker, 2001. The start of the geophysical
studies in this area dates back to several decades ago, but only after 1990
instrumental passive seismology started to be widely applied to investigate the
crustal properties and the properties of the seismic sources responsible for the strong
seismicity level observed along the Scotia plate boundaries. ASAIN started
operation in 1992 when a temporary seismograph was installed at the
Argentinean Base Esperanza. It grew quickly during the nineties and today five
stations are operated in Antarctica and two in Tierra del Fuego. All the Antarctic
stations transmit real-time data to the OGS and to the Instituto Antartico
Argentino. Esperanza (ESPZ), Jubany (JUBA), San Martin (SMAI) and
Orcadas(ORCD) stations also participate in the Virtual European Seismographic
Broadband Network (VEBSN) transmitting real time data to the Orfeus Data
Centre. On January 16 , 2009 BELA station was added to the network. It is
operated at the southernmost Argentinean Base Belgrano II (77° 52' S,
34° 37' W ) located on a rocky outcrop (Nunatak Bertrab) on the Filchner barrier. Its
inclusion in the VEBSN is also planned. ASAIN data real-time acquisition is
performed using SCREAM software, but also Earthworm and Antelope
software are being tested at the OGS Seismological Research Centre.UnpublishedErice (PA), Italy1.8. Osservazioni di geofisica ambientaleope
ASAIN: An Expanding Multipurpose Broadband Network for Seismological Research in Western Antarctica and Tierra del Fuego
No full textEtude sur «Amanita verna» (Bull.) Persoon (Basidiomycète Agaricales) récoltée dans la région lyonnaise
No full textRussi M., Josserand Marcel. Etude sur «Amanita verna» (Bull.) Persoon (Basidiomycète Agaricales) récoltée dans la région lyonnaise. In: Bulletin mensuel de la Société linnéenne de Lyon, 52ᵉ année, n°1, janvier 1983. pp. 6-10
Group velocity tomography in the Subantarctic Scotia Sea region.
No full textMore than 150 events, recently recorded by seven seismic broadband stations (OGS- IAA, IRIS, GSETT3-IDC), have been collected and processed to obtain an overview of the crust and upper mantle shear wave velocities.
Group velocities of the fundamental mode Rayleigh and Love waves, in the period range from 15 s to 50 s, are used to obtain tomographic maps of the Scotia Sea region, the tip of Antarctic Peninsula, and the tip of South America. Errors in the measurements, estimated on clusters, are larger for Love waves than for Rayleigh waves and their averages are 0.060–0.080 km/s and 0.030–0.040 km/s, respectively.
From the regionalisation of the dispersion measurements, we obtain smoothed local dispersion curves in correspondence with the main geological and tectonic features, and from their nonlinear inversion, the shear wave velocity versus depth profiles.
The correlation length of the heterogeneity, which can be resolved by Rayleigh waves, varies between 200 and 400 km in most parts of the studied area, but becomes greater near the periphery of the maps. The spatial resolution of Love waves (400–600 km) is poorer than that of Rayleigh waves, due to the deteriorated path coverage and to the larger errors in the group velocity measurements.
Models of the shear wave velocity in the crust and upper mantle for the tip of South America, the Falkland Plateau, the Scotia Sea, the South Sandwich oceanic spreading ridge, the South Sandwich trench, the South Scotia ridge, the tip of Antarctic Peninsula, the Bransfield Strait and the Drake Passage are presented.
Our regional models and the existing large-scale models (e.g., CRUST5.1), help to define a 3-D velocity model of the Scotia Sea region to be further investigated by waveform inversion
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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