1,720,957 research outputs found
Heavy mineral constraints on Paleocene sand transport routes in the Faroe-Shetland Basin
No full textAn integrated sandstone provenance study involving heavy mineral analysis, major element
geochemistry of garnet, trace element geochemistry of rutile, detrital zircon age dating and
palynofloral analysis has been undertaken on Paleocene (T10-T38) sandstones in hydrocarbon
exploration wells in the Faroe-Shetland Basin. This study has led to the identification of four
siliciclastic sand types, each with a different provenance, together with volcaniclastic detritus. Sand
type I was mainly derived from basement lithologies (Lewisian and/or Moine/Dalradian) on the
Orkney-Shetland Platform, either directly or indirectly through recycling. Sand type II was derived
principally through recycling of the Triassic on the Orkney-Shetland Platform. Sand type III, which
is commonly found in association with volcaniclastic material, is interpreted as having an origin on
the western margin of the basin. Sand type IV represents recycled Carboniferous (Namurian-
Westphalian) sandstones on the Orkney-Shetland Platform. Although the westerly-derived sand
type (III) has a zircon age spectrum dominated by the Archaean, the pattern contrasts with that
found in Archaean-derived Paleocene sandstones from the Kangerlussuaq region of East Greenland.
Derivation from more local Archaean basement is therefore inferred: possibilities include the crust
below the Faroe Islands, the Blosseville Kyst of East Greenland and the Wyville-Thomson Ridge.
Palynofloral analysis indicates that sand type III is invariably found in association with the
‘Greenland flora’, providing further support for input from the west. Most of the terrigenous sand
was supplied from the Orkney-Shetland Platform, but western input is seen locally at T10, T35-T36
and T38 levels
Constraining basalt thickness and sub-basalt velocities by combined analysis of ocean-bottom seismic and streamer data
No full textCombined analysis of ocean-bottom seismometer (OBS) and streamer data is critical in reducing
uncertainty in sub-basalt exploration. A major concern is that errors in basalt thickness and sub-
basalt velocities could result in a missed target in drilling; a mis-identification of base basalt can
change the geological model. Standard streamer data analysis offers poor velocity estimation below
top basalt while standard OBS data analysis gives weak depth control on base basalt. We provide
extra constraint by interpreting the full offset extent of base basalt reflections and basalt diving
waves. Our multi-step methods are: 1) identifying base basalt wide-angle reflections in OBS data
and then their equivalent in the streamer data; 2) tracing the near-offset continuation of both wide-
angle reflections into the respective water wave cones by means of multiple removal through
predictive deconvolution, block shift and fk-filtering; 3) inverse ray modelling the basalt velocity
using refracted basalt arrivals and base basalt depths from the full offset range of the base basalt
reflection; 4) inputting model results to pre-stack depth migration velocity for modelling deeper
layers. Here, we present results using data from the integrated Seismic Imaging and Modelling of
Margins (iSIMM) Project, acquired across the Faroe-Shetland basin. Our results show well-
constrained basalt velocities increasing from 4.5km/s at the top to 5.5km/s at the base, and
thicknesses of up to 3km where basalts overlie a low velocity zone. A geologically-satisfying model
of this low velocity zone is presented, with its base matching an observed basement reflection
Imaging igneous intrusions in the lower crust on the Faroes and Hatton Bank margins using wide-angle Ocean Bottom Seismometer data.
No full textStacked seismic sections produced from wide-angle ocean bottom seismometers (OBS) show clear,
strong P-wave reflections interpreted as igneous intrusions arriving from lower crustal and upper
mantle depths on the Faroes margin. The lower-crustal reflectors are also seen on a coincident long-
offset multi-channel (MCS) profile, though the upper mantle reflections are a new observation.
Strong wide-angle reflections are also seen in OBS data from Hatton Bank profiles where no
corresponding MCS profiles were shot. Applying this technique to the Hatton Bank data will allow
us to image this section of the margin and determine if the structure seen in the Faroes MCS survey
is present at other locations along the margin. Producing such images with conventional MCS data
has proved difficult due to their necessarily limited offsets, and the presence of refractions and
multiples at offsets beyond the first break of the sea-bed reflection. Adapting this technique to the
OBS shear wave data may allow us for the first time to image sub-basalt structure with converted
shear waves. Our results demonstrate the benefit of imaging wide-angle OBS data, since many OBS
surveys have been employed solely to perform travel-time inversions. The data come from the
integrated Seismic Imaging and Modelling of Margins (iSIMM) project shot in 2002 with wide-
angle OBS surveys northeast of the Faroe Islands and across Hatton Bank. These areas contain
flood basalts of the North Atlantic Igneous Province, making conventional seismic imaging
challenging
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
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
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
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
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