1,721,058 research outputs found
CRYSTAL CHEMISTRY OF CLINOPYROXENES IN SPINEL-PERIDOTITE MANTLE XENOLITHS FROM THE FERNANDO DE NORONHA OCEANIC ISLAND (NE-BRAZIL)
No full textSix c2/c clinopyroxenes (cpx) of spinel peridotite mantle xenoliths enclosed in the alkali basalts from the Fernando de Noronha (FN) oceanic island (NE-Brazil) were studied by means of X-ray diffraction (single crystal) and electron microprobe analyses. Fn-cpx crystal chemistry was compared with those of clinopyroxenes of spinel-peridotite mantle xenoliths enclosed in alkali basalts related to continental extensional tectonics from NE-Brazil and Mt. Leura (Australia). The equilibration pressure estimates by FN-cpx crystal chemistry through cell and site volumes relationships evidences as the mantle xenoliths from Fernando de Noronha oceanic island were sampled at higher depth with respect to the continental analogues from NE- Brazil
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
Geochemical and isotopic features of Ferrar magmatic Province (Victoria Land, Antarctica)
No full textVariations 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
Inter- and intracrystalline temperature and pressure estimates on pyroxenes from NE Brazil mantle xenoliths
No full textMercier's thermobarometer (Mercier 1980) and Saxena's thermometer (Dal Negro et al. 1982) were applied to single pyroxenes of both porphyroclastic (PF) and protogranular (PR) spinel peridotitic nodules enclosed in alkaline products related to necks of North-Eastern Brazil. Intercrystalline temperatures obtained using both orthopyroxene (opx) and clinopyroxene (cpx) compositions were in agreement, and were lower in protogranular than in porphyroclastic nodules (1051±57 and 1266±19°C respectively). In contrast, pressure estimates using cpx and opx were conflicting, in particular as regards PF nodules. In fact for PF nodules cpx compositions point to 27–32 kbar (mean 29±2) whereas opx compositions point to 17–19 kbar (mean 18±1). Conversely, PR nodule cpx and opx compositions point to similar values 17–24 and 15–18 kbar respectively (mean 19±4). The result obtained for PF nodules using cpx composition clearly contrasts with petrographic evidence and it is due to the peculiar composition of PF cpx (e.g. low Ca content, from 0.645 to 0.737 atoms per formula unit, a.f.u.) that strongly affects the barometric formulation. The PR and PF cpxs reveal similar mean intracrystalline temperature estimates (712±112 and 778±217°C, respectively). These, considering the difference of about 200°C in the intercrystalline temperature estimates, indicate that the exchange cation reaction between the M1 and M2 sites was a faster process in PF than in PR cpx, favoured by the low Ca content of PF cpx. Thus alternatively, the composition of PF cpx, characterized by a high rate of Ca » Mg substitution in the M2 site, may not affect the intercrystalline temperature. Therefore the difference of about 200°C found in intercrystalline temperatures between PR and PF cpxs, in spite of their same pressure values, may be interpreted as indicating an anomalous temperature gradient in the region
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
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