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Carbonaceous chondrite NWA 4446
No full textThe authors carried out petrographic, mineralogical, and chemical analyses (bulk chemical composition and microanalyses of mineral chemical composition) of NWA 4446 carbonaceous chondrite. NWA 4446 chondrite is classified as CV3, S2, W2. This meteorite is a rock fragment most likely from one of the C-type asteroids orbiting the Sun in the outer part of the asteroid belt. It represents the matter formed at the earliest stages of the formation of extrasola bodies in the solar system. As a result of the research, the authors documented a wider range of variation in the chemical composition of olivine crystals (Fa: 0.67-46.57 mol%) in the matrix and chondrules, and a much narrower range of variation in the chemical com- position of pyroxene crystals (Fs: 0.90–3.35 mol%) against the data used for the classification of the meteorite. The characteristics of the chondrules, ranging in size from 0.5 to more than 1 mm, allowed concluding that they constitute about 60% of the meteorite’s vol- ume, in which they form many structural and mineral varieties PO, POP, BO, PP and RP chondrules were observed. The remaining 40% of the chondrite volume is a matrix consisting of small crystals of pyroxenes, olivines, glass, as well as opaque minerals: sulphides, FeNi alloy, native copper and gold grains, carbonaceous substance, and compact CAIs. The mineral and chemical composi- tion of CAIs shows that their dominant mineral is melilite, accompanied by diopside and spinel. The chemical composition of spinel and diopside is very similar to their total chemical formulas, while the composition of melilite shows a significant sodium deficiency. Among the opaque minerals, one phase of the FeNi dominates - awaruite (Ni 3 Fe), and sulphides are represented by troilite (FeS) and mackinawite ((Fe,Ni) 9 S 8 ). Moreover, grains of native copper with an admixture of gold and grains of native gold with an admixture of platinum, nickel and copper with a size of several μm were identified. Taking into account the admixtures contained in the above-mentioned opaque minerals (mainly Co and Cu), the parent rock of the carbonaceous chondrite NWA 4446 can be considered to have been mineralized with Fe, Ni, Co and Cu ore minerals with the content of Au and Pt. This means that, we can expect deposits of native forms of the above-mentioned metals and sulphides on the parent bodies of carbonaceous chondrites of the CV group - C-type asteroids
Rim fragment of a shallow bowl White Painted II (120572/4446).
No full textRim fragment of a shallow bowl White Painted II (120572/4446).</p
Linked collectors and determiners for: University Of Pretoria: Lacewing Database Project (1911-2015).
No full textNatural history specimen data linked to collectors and determiners held within, "University Of Pretoria: Lacewing Database Project (1911-2015)". Claims or attributions were made on Bionomia by volunteer Scribes, <a href="http://bionomia.net/dataset/cc3b1f69-482e-4446-964a-9bbbea66429f">https://bionomia.net/dataset/cc3b1f69-482e-4446-964a-9bbbea66429f</a> using specimen data from the dataset aggregated by the Global Biodiversity Information Facility, <a href="https://gbif.org/dataset/cc3b1f69-482e-4446-964a-9bbbea66429f">https://gbif.org/dataset/cc3b1f69-482e-4446-964a-9bbbea66429f</a>. Formatted as a Frictionless Data package
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
Linked collectors and determiners for: Unveiling the diversity of Phalangodus Gervais, 1842 (Opiliones: Cranaidae): descriptions of four new species from Colombia.
No full textNatural history specimen data linked to collectors and determiners held within, "Unveiling the diversity of Phalangodus Gervais, 1842 (Opiliones: Cranaidae): descriptions of four new species from Colombia". Claims or attributions were made on Bionomia by volunteer Scribes, <a href="http://bionomia.net/dataset/9010e0ee-8975-4446-b752-52bb9bc64eb2">https://bionomia.net/dataset/9010e0ee-8975-4446-b752-52bb9bc64eb2</a> using specimen data from the dataset aggregated by the Global Biodiversity Information Facility, <a href="https://gbif.org/dataset/9010e0ee-8975-4446-b752-52bb9bc64eb2">https://gbif.org/dataset/9010e0ee-8975-4446-b752-52bb9bc64eb2</a>. Formatted as a Frictionless Data package
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
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