1,720,958 research outputs found
The Mount Pavagadh volcanic suite, Deccan Traps: geochemical stratigraphy and magmatic evolution
No full textThe patterns of eruption and dispersal of flood basalt lavas on the surface, or as magmas in dykes and sills within the crust, determine the volcanological and stratigraphic development of flood basalt provinces. This is a geochemical and Sr-isotopic study of lavas of varied compositions that outcrop around Mount Pavagadh (829 m), Deccan Traps, an important outlier north of the main basalt outcrop. Most of the similar to 550-m thick exposed section at Pavagadh is made up of subalkalic basalts rich in the incompatible elements (particularly Nb, Ba, and Sr). Picrite and rhyolite-dacite flows also occur, the latter capping the sequence. The relatively high initial Sr-87/Sr-86 ratios (up to 0.7083) and chemical characteristics of the rhyolitic rocks of Pavagadh are consistent with a small but significant involvement of the granitic basement crust in their genesis. An assimilation-fractional crystallization (AFC) model involving the picrite lava and either a southern Indian or a western Indian granite as the contaminant explains the geochemical and Sr-isotopic variation in the basalts and the rhyolites quite well. A systematic comparison of the basaltic lavas (with binary plots, normalized multielement patterns, and discriminant function analysis) to the well-established lava stratigraphy of the Western Ghats, 400-500 km to the south, precludes any chemical-genetic relationships between the two. Basalts exposed in sections closer to Pavagadh ((similar to) 150-200 km), in the Toranmal, Navagam, and Barwani-Mhow areas, have several flows with some similar chemical characteristics. However, the Pavagadh sequence is significantly different from all of these sequences geochemically, petrogenetically, and in magnetic polarity, to be considered independently built. This result is significant in terms of eruptive models for the Deccan Traps, as it is increasingly apparent that there were separate but possibly coeval eruptive centers with their own distinctive chemistries developed in various areas of this vast province
Correlations between silicic volcanic rocks of the St. Mary’s Islands (southwestern India) and eastern Madagascar: implications for Late Cretaceous India-Madagascar reconstructions
No full textThe St Mary's, Islands (southwestern India) expose silicic volcanic and sub-volcanic rocks (rhyolites and granophyric dacites) emplaced contemporaneously with the Cretaceous igneous province of Madagascar, roughly 88-90 Ma ago. I he St Mary's Islands rocks have phenocrysts of plagioclase, clinopyroxene, orthopyroxene and opaque oxide, Moderate enrichment in the incompatible elements, (e.g. Zr 580 720 ppm, Nb 43 53 ppan, La/Yb(a) 0.9 7.2), relatively low initial (87)Sr/(86)Sr (0.7052 0.7055) and near-chondritic initial (143)Nd/(144)Nd (0.51248 0.51249), They have mineral chemical, whole-rock chemical and isotopic Compositions very close to those of rhyolites exposed between Vatomandry Ilaka and Mananjary in eastern Madagascar, and are distinctly different from rhyolites front other sectors of the Madagascan province. We therefore postulate that the St Mary's and the Vatomandry-Ilaka Mananjary silicic rock outcrops were adjacent before the Late Cretaceous rifting that split Madagascar from India, If so, they provide a valuable tool to check and aid traditional Cretaceous India Madagascar reconstructions based on palaeomagnetism, matching Precambrian geological features, and geometric fitting of continental shelves
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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