1,721,053 research outputs found
Neoarchean double-sided subduction and continent-continent collision during the assembly of the Kenorland supercontinent: a new tectonic model for the Limpopo Complex in southern Africa
Full text linkThe 15th Symposium on Polar Science/Ordinary sessions [OG] Polar geosciences, Wed. 4 Dec. / Entrance Hall (1st floor), National Institute of Polar Researchconference outpu
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
始生代の泥質岩にみられる化学組成の多様性 : 南部アフリカ,カープバールクラトンおよびリンポポ帯の例
No full textMajor and minor elements chemistry of Archean pelitic rocks was analyzed by X-ray fluorescence spectrometer. Samples were collected from three different terranes in southern Africa; Barberton and Sutherland greenstone belts in the Kaapvaal Craton, granulite terrane of the Southern Marginal Zone of the Limpopo Belt, and supracrustal sequences of the Central Zone of the Limpopo Belt. Although bulk chemical composition varies from sample to sample, pelitic rocks from the Kaapvaal Craton exhibit similar composition to those from the Southern Marginal Zone. In contrast, those from the Central Zone have wide compositional range probably because they were supplied from many different sources.
An enrichment in Ni and Cr in pelitic rocks from the Kaapvaal Craton and Southern Marginal Zone was well observed. The Ni and Cr contents increase from 30 to 260 ppm and 10 to 580 ppm (Central Zone) to 280 to 550 ppm and 710 to 1410 ppm (Southern Marginal Zone and Kaapvaal Craton), respectively. The enrichment in Ni and Cr in particular pelitic rocks can be inferred from the presence of high Ni- and Cr-bearing rocks (komatiite?) on the earth surface during sedimentation
二次イオン質量分析法による隠岐島後産泥質片麻岩のジルコン年代(予報)
No full textSingle zircon U-Pb analytical technique by SIMS (secondary ion mass spectrometry) was applied to metasediment from Oki-Dogo Island, southwest Japan. ^Pb/ ^Pb age of zircons comprise three generations; 2.3, 2.0, and 1.7 Ga. Well-rounded crystal shape of the analyzed zircons suggests that the sediments are detritus of a continental land mass which was Proterozoic in age. The age dispersion may be attributed to at least three individual magmatic activities in the Proterozoic continent
南アフリカ、サザーランド・グリーンストン帯、クレイン・レタバ鉱山産泥質片岩中のざくろ石にみられる組成累構造
No full textThe Sutherland Greenstone Belt, located near the northeastern edge of the Kaapvaal Craton in South Africa, is composed mainly of Archean metasedimentary and metavolcanic rocks of amphibolite grade. Sample of pelitic schist collected from Klein Letaba Mine contains mineral assemblage of quartz, plagioclase, garnet, biotite, anthophyllite, gedrite, kyanite, staurolite, and tourmaline. Compositional profile of euhedral garnet shows growth zoning pattern (Fe+Mg increases and Ca+Mn decreases continuously from core to rim) which was produced during prograde metamorphism. In contrast, edge of the garnet is characterized by reverse trend; Fe+Mg decreases and Ca+Mn increases from rim to edge. The garnet is considered to have suffered subsequent overgrowth or modification of composition near the edge of the crystal after peak metamorphism. The retrograde event may be associated with thrusting of the high-grade Limpopo Belt onto the low-grade Kaapvaal Craton
Post-peak incipient charnockite formation in the Neoproterozoic Trivandrum Block, southern India: new insights from monazite Th-U-total Pb geochronology
Full text linkThe 14th Symposium on Polar Science/Ordinary sessions [OG] Polar geosciences, Wed. 15 Nov. / Entrance Hall (1st floor), National Institute of Polar Researchconference objec
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
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