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Paleoenvironmental interpretation of the Amynteon-Ptolemaida lignite deposit in northern Greece based on its petrographic composition
No full textThe objective of this study was to reconstruct the paleoenviromnent during formation of the deposit at Amynteon-Ptolemaida based mainly on its petrographic but also supported by its paleobotanic character and fossils found in the lignite beds themselves. The deposit of Amynteon occurs in the northern part of the elongated basin of Ptolemaida-Amynteon. The type of lignite formation is, in general terms, similar to the deposit of Ptolemaida, and the lignite is present in the Pleistocene strata of the basin. The alternating nature of lignite and interburden is an important characteristic of the deposit. In this study, we selected 20 samples of lignite from a representative drillhole, namely B-258 in order to discern its petrography. Optical microscopy showed that the huminite group macerals are dominant, ranging from 42.5% to 95.3%. Humotelinite is present in low to high quantities (12.0-79.5%), followed closely by humodetrinite. Humocollinite is present in very small amounts. In addition, macerals of the liptinite and inertinite groups are found in small concentrations, with a few exceptions. A number of indices, such as gelification index (GI), vegetation index (VI), groundwater index (GWI), tissue preservation index (TPI), and their ratios (e.g., VI/GWI, TPI/GI), were used to reconstruct the conditions prevailing during peat formation. The results indicate that the paleoenvironment was mainly limnic at the initial stages and transitioned to limnotelmatic with occasional rheotrophic conditions. The organic matter responsible for lignite formation developed mainly in a forested swamp environment with occasional transitions either towards a wet limnic (open water) or a drier telmatic environment. (C) 2003 Elsevier B.V. All rights reserved
Petrographical, palynological, and sedimentological aspects regarding the genesis of palaeogene lignites near Alexandroupolis, Thrace, Greece
No full textSeveral minor lignite deposits of Palaeogene (Eocene to Oligocene) age occur in the vicinity of Alexandroupolis, Thrace, northern Greece. A few rather thin seams were mined in the past by small private operations for local use. Coal samples have been collected from old mine dumps and outcrops around abandoned mine posts to be studied by means of maceral analysis at high magnification. The groundwater and vegetation index are calculated from the maceral composition and used to draw conclusions concerning the environment of deposition. In addition, block samples of coal cut perpendicular to bedding were studied at intermediate magnification and under fluorescence thus revealing some interesting bedding features as well as well-preserved plant organisms. The coals are characteristically finely laminated and highly gelified.
Palynological preparations have thus far yielded only poorly preserved palynomorph assemblages rather low in diversity and dominated by fern spores. This fern dominance is rather unusual; however, it is compatible with the occurrence of fertile fern fronds observed in petrographic coal sections.
Accompanying clastic sediments exhibit cyclic fining-upward sequences at a scale averaging about 1 m in vertical extent. Grain sizes range from small gravel to clay and silt. In some cases, siltstones in the roof of coal seams include abundant plant fragments showing parallel venation. The evidence presented from various sources suggests a rather unstable fluvial environment and a generally high water table on the flood plain for the formation of these lignites
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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