1,721,072 research outputs found
Sedimentología y diagénesis de la barra carbonatada inferior del Muschelkalk en la rama aragonesa de la Cordillera Ibérica. ( PROVINCIA DE ZARAGOZA )
Full text linkDepto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu
Comparative analysis of two Miocene carbonate platforms: a distally steepened ramp (Menorca, Spain) and a low-angle ramp (Latium Abruzzi, Italy)
No full textCharacterization of upslope migrating cross-bedded deposits in a carbonate ramp (Upper Miocene, Menorca, Balearic Islands, Spain)
No full textMenorca is subdivided in main regions with different stratigraphic and tectonic characteristics. To the north, folded, thrusted and faulted Paleozoic, Mesozoic and Paleogene rocks compose the Tramuntana region. To the south, upper-Miocene carbonate and, locally, siliciclastic rocks compose the Migjorn region. Upper Miocene rocks unconformably overlie Paleozoic to middle Miocene basement. In the Migjorn, three Miocene depositional units were recognized (Pomar et al., 2002 and references herein): the Basal Conglomeratic Unit (Burdigalian p.p.), interpreted as near-shore to fan-delta deposits; the Lower Bar Unit (early Tortonian), interpreted as a distally steepened carbonate ramp; the Reef Complex (upper Tortonian - lower Messinian), a reef-rimmed platform prograding complex. Within the ramp, Pomar et al. (2002) distinguished four facies belts: fan-delta conglomerates and bioturbated packstones (inner ramp), crossbedded grainstones (middle- ramp), rhodolithic rudstone clinobeds (ramp slope) and fine-grained wackestone-packstone with planktonic foraminifers (outer ramp). The cross-bedded units here analysed occur at the transition lower slope-outer ramp. They infill the axial depression of large slide/slump scars. These scars truncate the gently, 10°-12° basinward dipping, slope-to-outer ramp succession.
The wedge-shaped cross-bedded units, 10-12m thick, pinch out basinward and extend laterally for tens of meters. Several amalgamated cross-laminated bodies, 40cm- to 2m wide each with erosive base compose each unit.
They are composed by rhodolithic-mollusk rudstone with coarse grain/packstone matrix. Porosity is very high, cementation low and dolomitization patchy. Matrix consists of red-algal-, bivalve-, echinoderm, coral fragments, and benthic foraminifers. Ooids are, locally abundant along with limestone pebbles. Pebbles are flat, 5- to 10-cm wide, of oolitic grainstone, sometimes with mollusk borings. Cross bedding is underlined by the abundance and orientation of coarser components. Cross-laminae within units dip upslope (8° to 35°) forming backstepping backsets. Upslope bedform migration has been explained as forming when a supercritical flow encounters a local obstruction (or a local break on the slope), and a hydraulic jump may occur within the flow, upcurrent from the obstruction. Sediment will be therefore deposited at the obstruction forming an up-flow-dipping slipface that will tend to accrete and migrate in the upflow direction. In Menorca, these sedimentary structures have been interpreted by Pomar et al. (2002), as backset beds related to up-stream migrating hydraulic jump where slide scars acted as slope channels funneling platform debris down the slope.
The occurrence of aragonitic components (oolites, corals) within these units, absent in the ramp system, and the scars development at the end of the ramp progradation, suggest the involvement of Reef Complex sediment. Therefore, those events, involved both sediment of the upper Tortonian distally steepened ramp and part of the Reef Complex.
These structures have been mostly described in different environments of terrigenous systems. In carbonate systems are scarcely described and none from carbonate ramps. The architecture characterizing these upslope cross-bedded beds seams to call for a scour-and-fill process, therefore initially the action of a strong scouring event immediately followed by depositional events. The presence of these bodies in various intervals suggests the repetitive occurrence of this process.
In the studied system, deep-scouring events on the platform could be represented by slope failures that induced tsunami events or by eustatic variations, able to create strong downslope flows directed offshore. Scours have been rapidly infilled by shallow-water sediment
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
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