1,721,016 research outputs found
Hemimorphite-like phase bioprecipitation by Leptolyngbya frigida in a metal extreme environment
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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
Supergene non-sulfide Zn deposits: could hemimorphite have a biological origin?
No full textHemimorphite, Zn4Si2O7(OH)2·H2O, is one of the most common minerals in non-sulfide Zn deposits, together with
hydrozincite and smithsonite. Precipitation of hemimorphite during the supergene evolution of non-sulfide Zn deposits
is a debated issue (Choulet et al., 2014; McPhail et al., 2003) in which the scientific community has given till now a
traditional inorganic geochemical explanation and, despite their importance for the development of ore genesis and
metal dispersion models, the stability properties of hemimorphite are poorly known. Our research is right addressed to
understanding the hemimorphite stability performing solubility experiments in free-drift batch reactors on inorganic
hemimorphite, from a supergene non-sulfide Zn deposit, and biological hemimorphite precipitated by bacterial activity.
Solid samples were characterized, before and after the solubility experiments, exploiting laboratory and synchrotron
radiation based multi-technique approach that combines X-ray powder diffraction (XRPD), Scanning Electron
Microscopy (SEM), and X-ray Absorption Spectroscopy (XAS). The calculated solubility product constants (logKs) are
similar for both “geological” (logKs = 30.3±0.4) and biogenic hemimorphite (logKs = 30.5±0.1). We demonstrate that
the solubility experiments trigger an amorphous to crystalline phase transition of biological hemimorphite, while
mineralized bacterial sheaths and organic filaments, that allowed us to demonstrate its biological origin, were dissolved
and no longer recognizable by Scanning Electron Microscopy.
This study provides new thermodynamic data on hemimorphite allowing us to present improved predominance
diagrams (PCO2 vs. pH) for the chemical system Zn – O – H – C – Si, which may be useful for developing genetic
models of ore deposits, for predicting mineral dissolution/precipitation reactions and for investigating metal dispersion
processes. The amorphous to crystalline state transition of bio-hemimorphite associated to the obliteration of its biomorphological
features, open up the question if bacteria could have played a role in the formation of hemimorphite
deposits. Such interaction between biosphere and geosphere raises an important question about the possibility of using
endemic bacteria to develop more sustainable technologies for Zn abatement and recovery in abandoned mine systems
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
XRD-thermal combined analyses: An approach to evaluate the potential of phytoremediation, phytomining, and biochar production
Full text linkA method for evaluating the potential of reuse of biomasses for economic purposes is here presented starting from a case study. Juncus acutus plants and rhizospheres were harvested from abandoned Zn-Pb mine areas of southwest Sardinia (Italy). Thermogravimetry and Differential Thermal analyses were performed to evaluate the temperatures at which significant reactions occur. X-ray Diffraction (XRD) analysis was carried out on raw samples and on samples heated ex-situ (by a conventional diffractometer) or in-situ (by synchrotron-based diffraction). Raw samples mainly consist of quartz, phyllosilicates, and feldspars with minor amounts of sulfides, sulfates, and Fe, Pb, and Zn carbonates, concentrated in the rhizosphere. After heating, Zn and Fe oxides and willemite are observed in internal roots and stems, revealing the presence of these metals in the plant tissues. In-situ heating was less effective than ex-situ in revealing minor phases in organic samples, probably because the scarcity of oxygen within the sample holder did not allow the degradation of organic compounds and the oxidation of sulfides, resulting in a low quality XRD signal even if obtained with the high resolution ensured by a synchrotron light source. This method can be applied to plants from polluted sites for metal exploitation, and/or to biomasses from unpolluted sites for biochar production, since both applications take advantage of the knowledge of the minerals formed after heating
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