1,721,996 research outputs found
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
MINERALOGY, PETROLOGY, AND GEOCHEMISTRY OF THE UNIQUE SILICA-RICH UNGROUPED ACHONDRITE NORTHWEST AFRICA 11575
No full textWe report here on a unique, newly discovered, silica-rich ungrouped achondrite Northwest Africa 11575 (NWA 11575). NWA 11575 is one of four known silica-rich ungrouped achondrites, presenting evidence for igneous processes resulting in evolved compositions early in the history of the solar system. It is unique from the other silica-rich ungrouped achondrites in that it has pyroxene compositional trends matching those of lunar samples and martian meteorites; contains quartz and potassium feldspar; and contains oxygen, hydrogen, and chromium isotopes that are similar to those of LL chondrites. Together, these four silica-rich ungrouped achondrites provide evidence for evolved compositions resulting from igneous processes on at least three separate bodies.
NWA 11575 consists of two lithologies, the host or light lithology and the dark lithology. The dark lithology occurs as clasts within the light lithology, with a distinct contact between the lithologies. The mineralogy of the host lithology consists of 53.8% oligoclase, 34.1% pyroxene, 4.8% potassium feldspar, 3.8% quartz, and 2.6% apatite and merrillite, along with minor chromite, ilmenite, iron oxide, iron sulfide, and low-Ni iron. The apatite is three times more abundant than the merrillite. The dark lithology consists of 70% groundmass and 30% pyroxenes but has a similar trachyandesitic to andesitic bulk composition. Apatite is present in some regions within the dark lithology but is not ubiquitous. The pyroxene compositional zoning trend for the light lithology consists of magnesian pigeonite, mantled by an augitic layer, and then rimmed by ferropigeonite. Numerous similarities between the host and dark lithologies, such as similar oxygen isotopic compositions, bulk compositions, and pyroxene trends, suggest that the host and dark lithology are derived from the same source, but differ in their cooling and crystallization histories.
One possible interpretation is that the host and dark lithologies are lavas formed through extensive magmatic differentiation, possibly derived from a precursor of chondritic composition, which erupted on the surface of their parent body. The dark lithology cooled quickly forming a quenched glass with hopper pyroxenes. The later-erupted material, perhaps with more overlying material to insulate the magma and provide for a slower cooling rate, cooled slowly enough to crystallize complexly zoned pyroxenes, feldspars, and a residual mesostasis of quartz, potassium feldspar, apatite, and minor phases. Alternatively, the dark lithology could be an impact melt. Either process could have occurred on a volcanic parent body with oxygen isotopes similar to those of LL chondrites, or at some location on the LL-chondrite parent body itself
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
Collenette. Sh. — Wildflowers of Saudi Arabia. National Commission for Wildlife Conservation and Development (NCWCD), P.O. Box 61681, Riyadh 11575, Saudi Arabia. 1999
No full textGillet Hubert. Collenette. Sh. — Wildflowers of Saudi Arabia. National Commission for Wildlife Conservation and Development (NCWCD), P.O. Box 61681, Riyadh 11575, Saudi Arabia. 1999. In: Revue d'Écologie (La Terre et La Vie), tome 55, n°2, 2000. pp. 198-199
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
- …
