1,721,542 research outputs found
Metasomatismo del mantello dell'avambraccio mediato dai fluidi: approfondimenti dalla modellazione termomeccanica petrologica
No full textMantle metasomatism and associated fluid-aided mass transfer have wide-ranging implications for geochemical, rheological and dynamical aspects of the shallow Earth interior. However, large uncertainties remain due to the inaccessibility of metasomatic processes over geologic timescales, scarcity of samples and the fragmentary nature of outcrops. Despite chemically open-system behavior has been evidenced from geochemical and petrological records, most geodynamical modelling approaches rely on a chemically closed-system. Taking advantage of improved numerical techniques, and thermodynamic theories, we developed a new petrological–thermo–mechanical code to overcome such a closed-system limitation. This code use thermodyamically predicted rock solubility to monitor the mass exchange between rocks and coexisting fluids, and thermomechanically determined fluid and solid flow to simulate advection and potential dynamic feedbacks. Comparison with previously published numerical results justifies the robustness of this new method in spite of the differences in the employed solid solution models, thermodynamic database and coarser resolution (0.50.5km), which cause minor compositional differences mainly due to smoothing effects along lithological boundaries. We utilize this new code to explore the first-order redistribution patterns of rock-forming elements and newly formed metasomatic minerals as a function of convergence rates, slab ages and subducted sediment compositions. Youngest and slowest subduction zones with an abundant water supply from the slab experience the most notable element mobility. The progressive thermal cooling of subduction zones enhances the extent of mantle alteration. Lithological boundaries with steep compositional gradients are often affected by intensive fluid-mediated alterations and formation of metasomatinites as slab-derived elements are mostly absorbed along such boundaries. The multicomponent fluid compositions emanated from slabs evolve with slab depth, and associated alteration zones are characterized by a decrease in the phase proportions of antigorite, chlorite, and an increase of that of talc with depth near the slab-mantle interface. C- and Si-bearing fluids infiltration facilitates the formation of talc-rich metasomatinites at cold slab top conditions, whereas substantial carbon-poor fluids infiltration decomposes talc as slap top temperatures approach the solidus. Talc together with antigorite and chlorite likely play a significant role in element circulation as well as in controlling the bulk mechanical properties and seismicity along the plate interface at subduction zones. Overall, the obtained results are consistent with geophysical observations, petrological records, petrological experiments and reaction path model results. This work provides a promising tool for exploring the complex interplay among geodynamics of subduction zones, geochemical recycling occurring within the shallow planetary interior, and magmatic processes
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
Isolation and molecular characterization of the porcine stearoyl-CoA desaturase gene
No full textStearoyl-CoA desaturase (SCD) is a rate-limiting enzyme in the biosynthesis of unsaturated fatty acids. So far only a partial porcine SCD sequence is available. Here we described the isolation and molecular characterization of the full-length cDNA and the determination of the genomic DNA sequence of the porcine SCD gene. The 5134-bp cDNA contains a 1080-bp open reading frame (ORF) encoding a protein of 359 amino acids with a calculated molecular mass of 41.3 kDa and a theoretical isoelectric point of 9.4. The porcine SCD protein shares high identity (>80%) with the other mammalian SCD. To further elucidate the genomic structure of the porcine SCD gene, we sequenced 20,985 bp of genomic DNA sequence encompassing the complete pig SCD gene. Similar to the other mammalian orthologs, particularly in term of exon size and exon/intron boundaries, the porcine SCD gene spans a transcription unit of 16,186 bp, consisting of six exons with sizes ranging from 131 to 4048 bp, and five introns varying in size from 518 to 4784 bp. The gene reveals a 176-bp-long 5' UTR and possesses an unusually long 3'UTR of 3848 bp in the last exon. Comparison of different mammalian SCD promoters identified some regulatory domains required for the transcription regulation in the 5' flanking sequence of the porcine SCD gene, such as the conserved polyunsaturated fatty acid response region (PUFA-RE). A total of 21 gene polymorphisms were revealed in the 21-kb DNA sequence, including 19 single nucleotide polymorphisms (SNPs), a 24-bp-long fragment length polymorphism in the fourth intron and a triplet nucleotide insertion in the fifth intron. Reverse transcription (RT)-PCR result indicates that the SCD gene is expressed ubiquitously in pigs. (C) 2004 Elsevier B.V. All rights reserved
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
FIGURE 1 in A new Jurassic carnivorous cockroach (Insecta, Blattaria, Raphidiomimidae) from the Inner Mongolia in China
No full textFIGURE 1. Fortiblatta cuspicolor Liang, Vršanský et Ren sp. nov. Daohugou, Inner Mongolia, China. Middle Jurassic (the Late Aalenian or Early Bajocian): 1a. Line drawing of holotype (CNU-B-NN-2006-006); 1b. Photograph of holotype (CNU-B-NN-2006-006).Published as part of Ren, Jun-Hui Liang Peter Vršansk Ÿ Dong & Shih, Chungkun, 2009, A new Jurassic carnivorous cockroach (Insecta, Blattaria, Raphidiomimidae) from the Inner Mongolia in China, pp. 17-30 in Zootaxa 1974 on page 20, DOI: 10.5281/zenodo.18509
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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