1,720,993 research outputs found
Impact and conditions of calcite cementation on reservoir quality evolution of Upper Cretaceous limestones, Onshore Abu Dhabi, United Arab Emirates
No full textThis petrographic, stable isotopic, fluid inclusion and petrophysical study constrains the conditions of calcite cementation and its impact on reservoir quality of limestones of the Upper Cretaceous Simsima Formation across the anticline of an oilfield, onshore Abu Dhabi, UAE. The various crystal morphologies and occurrence habits of calcite cements and paragenetic relationshipsamong them and with other diagenetic minerals suggest various origins and formation timing. Scalenohedral and bladed calcite rims around allochems, which are restricted to packstones and grainstones, have precipitated as early cements from marine pore waters. Syntaxial calcite overgrowths around echinoid fragments engulf dolomite cement. Micro-thermometric measurement of fluid inclusions in one sample containing syntaxial calcite overgrowths revealed Th as lower as 64 oC and salinity of nearly 20.5 wt% NaCl equivalent corroborate an origin of fluids from a highly evaporative setting. The precipitation of coarse equant blocky calcite is common in limestones which display ample evidence of dissolution of peloids, which may have acted as source for this cement. An additional cement source is expected to by the incipient stylolitisation of the limestones. The presence of this late equant calcite, which post-dates and replaces moldic pore filling dolomite, both in the oil and water zones may pre-date the oil emplacement. However, in the oil zone these moldic pores have, in many cases, escaped cementation by calcite and were instead filled with oil indicating that oil emplacement retarded or even stopped diagenesis. The higher δ18OVPDB values of some of the micrite/microspar rich samples than the values expected for marine calcite precipitated at around 25o C were indicate that the waters were enriched in 18O due to evaporation or that precipitation occurred at low temperatures. Conversely, the coarse equant calcite cements have moderate depletion in δ18OVPDB (-6.2 to -3.2‰). Combining these relatively moderately negative oxygen
isotopic values with high homogenisation temperatures (76-95 °C) and high fluids salinity 16-19 wt% NaCl) suggest precipitation insemi-closed diagenetic systems from geochemically evolved formation waters. The higher homogenisation temperatures than maximum burial temperatures reached suggest that the role of flux of hot basinal brines on diagenesis of the limestones should not be ignored. The formation of secondary pores (e.g. vugs) might indicate that these brines were charged with organic acids
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
Governo del territorio, perequazione e compensazione territoriale: ipotesi di applicazione in Lombardia
No full textIL capitolo illustra i meccanismi perequativi e compensativi, introdotti recentemente dal legislatore regionale lombardo e il contesto applicativo e quello del Piano Terriotoriale Regionale della Lombardia e dei Piani Territoriali Regionali d'Area. Si analizza struttura finanziaria di tali piani, mettendo in rilievo l'importanza per tutti i territori interessati dal fenomeno della cooperazione intercomunale
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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