1,721,088 research outputs found
Stepwise post-glacial transgression in the Rhône Delta area as revealed by high-resolution core data
No full textIntegrated sedimentological and micropalaeontological (benthic foraminifers and ostracods) analyses of two continuous cores (40 m and 50 m long, respectively) recovered in the lower delta plain ofmodern Petit Rhône Delta, along with data from the previously studied Core SF, enable detailed reconstruction of the late Pleistocene–Holocene palaeoenvironmental evolution of the Rhône Delta system. Through identification of nine microfossil assemblages and with the aid of 28 radiocarbon dates, a high-resolution picture of stratigraphic architecture is offered for the
first time for the entire post-glacial succession.Above late Pleistocene fluvial-channel gravels, a retrograding pattern of swamp and estuarine/bay deposits (lower transgressive systems tract—TST) is overlain by vertically stacked, late transgressive nearshore deposits (upper TST). This succession reflects the progressive landward migration of the palaeoshoreline driven by the rapid post-glacial sea-level rise, which took place in the study area between ca. 12 and 7 cal ky BP. The following deceleration in sea-level rise (highstand phase) induced the onset of deltaic sedimentation, as evidenced by superposition of middle–late Holocene prodelta, delta-front and delta-plain deposits within the cored succession. At distal location the occurrence, within prodelta deposits, of a distinctive microfossil assemblage dominated by opportunistic benthic foraminifer Valvulineria bradyana marks the onset of the Rhône Delta mud-belt around 4 cal ky BP. Identification and lateral tracking of six separate flooding surfaces within the TST enable the characterization of five short-term (millennial to submillennial-scale) depositional cycles with distinctive transgressive–regressive internal architecture (T–R1–5). The lower, transgressive portions of cycles 1–3 (11.8–9.8 cal ky BP) mark abrupt shifts from freshwater to increasingly mixed, brackish-marine environments under conditions of rapid sea-level rise. In contrast, the upper, ‘regressive’ portions represent the filling of newly formed accommodation space via extensive crevasse to bay-head delta processes. Cycles 4 and 5 (9.8–8.2 cal ky BP) and the uppermost transgressive deposit below the maximum flooding surface document three distinct landward shifts of the shoreline that took place under conditions of rapidly increasing sea-level rise. The vertical stacking of these millennial-scale cycles is interpreted to reflect the stratigraphic response to stepwise sea-level rise during the early Holocene. The youngest flooding surface may represent the sea-level signature of the 8.2 ka climate event
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
High resolution ERT applied in sand-bed channel mouth infilling. The test site of Pégoulier channel in the Rhône Delta, France
No full textElectrical Resistivity Tomography (ERT) was applied in a sand-infilled paleo-channel located in the Rhoˆ ne Delta, in Southern France. The detailed pattern and sedimentological evolution of the channel fill deposits – know from both historical and geological sources – made it the ideal site to test the ERT method. A geoelectrical survey was performed, using the ABEM SAS-4000 multi-electrode array system in March 2003. Very low electrical resistivity values were obtained, ranging from 0.3 to 10 Ohm m, consistent with the high salinity measured in situ (the pore water conductivity was found to range from 0.9 to 1.2 S/m at 25 C). The electrical resistivity profiles reflect mainly salinity variations. Indeed, in this case, salinity is so high that surface conductivity associated with clay minerals can be safely neglected. ERT provided valuable high-resolution information that complemented other exiting data such as historical information, bathymetric, geological, and lithostratigraphic data, which allowed the architecture of the channel to be defined. The ERT was used to determine the infilling dynamics of the Pe ́ goulier Channel, which opens new perspectives in terms of paleoenvironmental reconstruction and paleodynamic studies
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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