1,720,981 research outputs found
State of the art: Italian carbonatites and their potential for critical-metal deposits
No full textThis paper is an updated overview, including many new data, of what is known about Italian alkaline–carbonatite complexes, plus a new description of a carbothermal residua-related district, and its potential for mineral deposits. The Italian carbonatite occurrences can be divided into two belts. The first is a 350 km long and 75 km wide belt along the Apennines mountain range mainly with primary extrusive carbonatites generally from monogenic volcanoes and from the Vulture volcanic complex; the second belt is 60 km long and 20 km wide in the Northern Latium region in which carbothermal residua carbonatites and fluorite mineralisation deposited by high-temperature fluids rich in CO2, SO2 and fluorine are occurring in caldera volcanoes. Several of the raw materials, such as Light Rare Earth Elements, vanadium, niobium, zirconium, fluorite and phosphate are identified as critical as well as other commodities, occur in Italian carbonatites and alkaline rocks. At the Pianciano quarry (Bracciano) fluorite-rich ore (fluor-ore = fluorite in a mineralised gangue) is actually exploited as flux for cement, but Rare Earth Elements (+ V) could be a notable by-product (300,000 metric tonnes, equivalent to 4.2% of European resources). Pyrochlore, monazite, apatite, and britholite bearing subvolcanic rocks in ejecta from the Vulture volcano are of a near-economic grade, but their geological constraints are not known. A conceptual framework of combined geological and geochemical data improves the general understanding of this regional magmatic system, aimed at laying the foundations of a future geological model disclosing unrecognised potential exploration targets. However, this paper is not intended for direct use by the exploration industry; rather it is principally aimed at mineralogists and petrologists who could develop strategies for the identification of unexposed or unrecognised deposits
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
Hydrothermal Mineral Deposits Principles and Fundamental Concepts for the Exploration Geologist
No full textOre Deposits and Mantle Plumes
No full textPERTH Western Australia March 2000 Increasingly explorationists are seeking to find new ore deposits in poorly prospected areas, be they geographically remote, such as in the Arctic, or geologically remote, such as those under sedimentary cover. Modern prospecting techniques, including low-detection-level geochemistry and the use of advanced geophysical instrumentation have greatly assisted explorers but fundamental to any soundly based exploration program remains an understanding of the geological framework of ore deposits. This allows the development of deposit models on macroscopic and mesoscopic scales. This book by Dr. Franeo Pirajno draws on his extensive and wide global experience. To set the scene for a discussion of ore deposit generation Franeo details the Earths internal structures and mantle dynamics. He then explores the impact of mantle plumes on the crust and in particular their role in the production of magmatic environments, and in continental scale rifting. This includes a descriptive section on magmatic provinces around the globe, which highlights the importance of plumes. Any study of Earth processes needs to take into account the effects of extraterrestrial bombardment, and in particular the results from the impacts of large bolides. The effects of these impacts on the atmosphere and on life have now been recognised as profound. It is likely that the effect ofthese impacts on the Earth's crust is as equally profoun
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