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Author Correction: Reliability of Total Grain-Size Distribution of Tephra Deposits (Scientific Reports, (2019), 9, 1, (10006), 10.1038/s41598-019-46125-8)
No full textAn amendment to this paper has been published and can be accessed via a link at the top of the paper
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
On the Features of Pyroclastic Deposits and Post-eruption Natural Hazards
No full textPyroclastic deposits of volcanic explosive eruptions are associated with both sedimentation of tephra and emplacement of pyroclastic density currents (PDCs) that travel on the flank of volcanoes. Pyroclastic deposits are typically mixtures of ash, lapilli and blocks, very loose and unconsolidated, hence prone to move along a slope. Due to highly porous structure, such deposits are also prone to wetting induced collapse, with a transition from a solid-like behaviour to a fluid-like behaviour. It entails a long run-out of mass-movements (landslides or lahars and debris flows) eventually triggered. Disasters associated with this type of deposit remobilization have been recorded all over the world even decades or centuries after the end of an eruption. Here we provide new insights into remobilization of tephra deposits based on various international case studies, bridging a gap among the different dataset and interpretations. Exponential and power relations are found among the uniformity coefficient, the median diameter and the main physical variables adopted in the physical-based models used for the analysis of the natural hazards in volcanic deposits
Modeling tephra dispersal in absence of wind: Insights from the climactic phase of the 2450 BP Plinian eruption of Pululahua volcano (Ecuador)
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
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
Corrigendum to “Assessing tephra total grain-size distribution: Insights from field data analysis” [Earth Planet. Sci. Lett. 443 (2016) 90–107] (S0012821X16300577)(10.1016/j.epsl.2016.02.040)
No full textThe authors found a mistake in the formulation of the distribution named Bi-Weibull distribution reported in the equation (A.2) of the Appendix A. The error affects equation (4) (which is the same as eq. (A.2)) and Table 4 in the original manuscript. In equation (A.2) the normalization constants were missing and there was an error in the argument of the exponent. The correct normalized distribution is:[formula fresented]. The corrected Table 4 and Fig. A.1 are reported below
Reliability of Total Grain-Size Distribution of Tephra Deposits
Full text linkTotal Grain-Size Distribution (TGSD) of tephra deposits is key to the characterization of explosive volcanism, plume-dispersal modeling, and magmatic fragmentation studies. Nonetheless, various aspects that includes deposit exposure and data fitting make its determination extremely complex and affect its representativeness. In order to shed some lights on the reliability of derived TGSDs, we examine a large TGSD dataset in combination with a sensitivity analysis of sampling strategies. These analyses are based both on a well-studied tephra deposit and on synthetic deposits associated with a variety of initial eruptive and atmospheric conditions. Results demonstrate that TGSDs can be satisfactorily fitted by four distributions (lognormal, Rosin-Rammler, and power-law based either on the absolute or cumulative number of particles) that capture different distribution features. In particular, the Rosin-Rammler distribution best reproduces both the median and the tails of the TGSDs. The accuracy of reconstructed TGSDs is strongly controlled by the number and distribution of the sampling points. We conclude that TGSDs should be critically assessed based on dedicated sampling strategies and should be fitted by one of the mentioned theoretical distributions depending on the specific study objective (e.g., tephra-deposit characterization, physical description of explosive eruptions, tephra-dispersal modeling)
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
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