1,721,012 research outputs found
Tectonic evolution of the Congo Basin using geophysical data and 3D numerical simulations
Full text linkThe Congo basin (CB) is an intracratonic basin that occupies a large part of the Congo Craton (1.2
million km2) covering approximately 10% of the continent [1]. It contains up to 9 km of
sedimentary rocks from the Mesoproterozoic until Cenozoic age. The formation of the CB started
with a rifting phase during Mesoproterozoic with the amalgamation of the Rodinia supercontinent
(1.2 Gyr). Afterwards, the main episodes of subsidence occurred during the subsequent
Neoproterozoic post-rift phases, which were followed by phases of compression at the end of the
Permian and during the Early Jurassic age and other sedimentation episodes during Upper
Cretaceous and Cenozoic [2].
We reconstruct the stratigraphy and tectonic evolution of the basin by analyzing seismic reflection
profiles. Furthermore, we estimated the velocity, density, and thickness of the sedimentary layers
in order to calculate their gravity effect. Afterwards, we calculate the gravity disturbance and
Bouguer anomalies using a combined satellite and terrestrial data gravity model. The gravity
disturbance obtained from the EIGEN-6C4 gravity model [3] shows two types of anomalies. One
with a long wavelength (~50 mGal) that covers the entire area of the Congo basin and a second
one with a short wavelength (~130 mGal), having a NW-SE trend, which corresponds to the main
depocenters of sediments detected by the interpretation of seismic reflection profiles. These
results have been used as input parameters for 3D numerical simulations to test the main
mechanisms of formation and evolution of the CB. For this aim, we used the thermomechanical
I3ELVIS code [4] to simulate the initial rift phase. The numerical tests have been conducted
considering a sub-circular weak zone in the central part of the cratonic lithosphere [2] and
applying a velocity of 2.5 cm/yr in two orthogonal directions (NS and EW), to test the hypothesis of
the formation of a multi extensional rift in a cratonic area. We repeated these numerical tests by
increasing the size of the weak zone and varying its lithospheric thickness. The results of these first
numerical experiments show the formation of a circular basin in the central part of the cratonic
lithosphere, in response to extensional stress, inducing the uplift of the asthenosphere.
[1] Kadima, et al. (2011), Structure and geological history of the Congo Basin: an integrated interpretation of gravity, magnetic and reflection seismic data,
doi:10.1111/j.1365-2117.2011.00500.x.
[2] De Wit, et al. (2008), Restoring Pan-African-Brasiliano connections: more Gondwana control,
less Trans-Atlantic corruption, doi:10.1144/SP294.20
[3] Förste et al. (2014) EIGEN-6C4 The latest combined global gravity field model including GOCE
data up to degree and order 2190 of GFZ Potsdam and GRGS Toulouse; doi:
10.5880/ICGEM.2015.1, 2014
[4] Gerya (2009), Introduction to numerical geodynamic modelling, Cambridge University Pres
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Data for: Sensitivity of gravity and topography regressions to earth and planetary structures
No full textResults of regression analysis between gravity and topography for Earth and Mars. The files contain the results of the regression analysis between the gravity field and topography calculated on sliding windows of 3° by 3° size. File 1: At each geographical location (defined by longitude and latitude node) slope, slope error, intercept of regression analysis for an area centered on the Atlantic Ocean of Earth. File 2: Residual gravity from regression analysis centered on Atlantic Ocean of Earth. File 3: at each geographical location (defined by longitude and latitude node) slope, slope error, intercept of regression analysis for Mars. Details of gravity and topography data used in main text of Article
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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