1,721,176 research outputs found
Petrogenesis of late Campanian alkaline igneous rocks in Eastern Anatolia: magmatism related to a subduction transform edge propagator (STEP) fault?
No full textIn eastern Anatolia, the Divriği-Hekimhan Magmatic Province (DHMP) includes ~77–69 Ma alkaline rock units which are located to the NW of the Baskil Arc of ~85–74 Ma. The magmatic rocks are composed of nepheline (Ne)–to quartz (Q)–normative alkaline basaltic to trachytic/syenitic units. Among them, the basaltic rocks are composed of plagioclase (Or 2–11Ab 32–51An 39–64) + clinopyroxene (Wo 47–51En 35–42Fs 9–16) + Fe-Ti oxide ± alkali feldspar (Or 57–98Ab 2–42An 1) ± biotite ± olivine. Their 87Sr/ 86Sr (I) ratios and ɛNd (I) values vary in the ranges of 0.70591–0.70871 and−3.2–1.6, respectively. The subvolcanic trachytic rocks are composed of perthitic alkali feldspar phenocryst in a matrix of feldspar (Or 45–61Ab 38–54An 0–2), biotite, and Fe-Ti oxides. The trachytic volcanic rocks are made up of feldspar (Or 38–63Ab 34–59An 1–4) in a fine-grained matrix. Their 87Sr/ 86Sr (I) ratios and ɛNd (I) values vary in the ranges of 0.70532–0.70952 and−3.2–0.7, respectively. The syenitic rocks in the region contain both quartz- and nepheline-sodalite-bearing syenites. Geochemical features reveal that the Ne-normative basaltic magmas have undergone mafic mineral fractionation coupled with crustal contamination to produce the Q-normative derivatives. Enhanced differentiation of the Ne- and Q-normative fractionated magmas via feldspar-dominated fractionation created the silica-undersaturated and -oversaturated trachytic magmas, respectively. During the feldspar-dominated differentiation, the re-melting of accumulated alkali feldspars in the magma chamber likely gave rise to the formation of trachytic rocks with alkali feldspar-like whole rock compositions. The final products of the Ne-normative magmas are represented by the phonolites and foid-syenites with silica-undersaturated eutectic compositions. A geochemical evaluation of the basaltic rocks revealed that the alkaline magmatism mainly originated from a shallow asthenospheric mantle source which had previously been metasomatized by oceanic to continental subduction. We suggest that the DHMP was formed in response to STEP fault-controlled rolling back of the northward subducting slab of the Baskil Arc, which created a localized gap for asthenospheric upwelling. </p
Late Mesozoic Tectono-stratigraphic evolution of the Hekimhan Basin and the environs (central eastern Anatolia): implications for the eastern Taurides and Gürün Curl
No full textThe east-west trending Taurides form a curved area in central eastern Anatolia known as the Gürün Curl. In order to understand the origin of the Gürün Curl and Tauride evolution in general, the results of a new field study of this region have been synthesized together with previously published data. We suggest that the geodynamic evolution of the area began with the likely presence of a Tethys Ocean transform fault. This fault separated the Taurides into the Akdere Sector in the west and the Munzur Sector in the east in the Late Cretaceous. During the late Santonian–early Campanian, ophiolites obducted onto the Munzur Sector, while platform sediments continued to accumulate in the Akdere Sector. This was followed by the development of an Andean-type arc-type magmatism (the Baskil Arc) during the early–middle Campanian in the Munzur Sector. Continued closure of the Tethys led to the collision of the Bitlis Massif in the south of the Munzur Sector in the Campanian. This, in turn, resulted in continental subduction and slab roll-back that was controlled by a Subduction Transform Edge Propagator (STEP) Fault that lay on the original transform fault between the Akdere and Munzur sectors. Because the subducted slab was free at its western corner, the western edge rolled back faster than in the east, leading to an asymmetrical extensional regime on the upper plate that created the late Campanian Hekimhan Basin. While these geodynamic events were taking place in the Munzur Sector, the Akdere Sector was in a platform setting. During the Palaeocene, the Late Mesozoic units of the Akdere Sector began to overthrust on the Hekimhan Basin and the ophiolites. Following the Palaeocene, all these tectonostratigraphic units were covered by Eocene sediments around the Gürün Curl of which the modern appearance was completed by the Miocene to Recent movements along the strike-slip faults.</p
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
Batı Anadolu graben sisteminde yer alan Simav Garbeninde tektonik aktiviteye dayalı radon anomalilerinin incelenmesi
No full textBu çalışmada, deprem önsezisi için toprak gazı radon konsantrasyonları, aktif Simav fay hattında LR-115 katı hal nükleer iz detektörleri ile ölçülmüştür. Haziran 2009’da kurulan radon gözlem ağı 24 istasyondan oluşmuştur. Radon gözlem ağında yer alan istasyonlardan elde edilen iki haftalık/aylık entegre toprak gazı radon ölçümleri, Simav fay hattında 2 Mart 2010’da oluşan M=4,2 büyüklüğünde ve diğer birçok küçük depremlerle ilişkili olabilecek değişimler göstermiştir. Batı Simav Grabeninde yer alan F4, F5, F9, F10 ve Doğu Simav Grabeninde yer alan F23 numaralı istasyonlarda, depremlerden önce ve sonra belirgin radon anomalileri gözlenmiştir. Bu radon gözlem projesinde, radon anomalileri meteorolojik koşullarla değişen sistematik bir ilişki göstermemiştir. Elde edilen bu veriler, çalışma alanında tektonik strese daha duyarlı kalıcı radon istasyonlarının oluşturulmasını sağlamıştır
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