1,721,393 research outputs found
Comparison between qualitative and quantitative rockfall risk methods for a hazardous road stretch
No full textIn order to compare rockfall risk values characterizing road sections affected by several rockfalls, two procedures have been used: the modified Colorado Rockfall Hazard Rating System (mCRHRS) and the ROckfall risk MAnagement (RO.MA.) method. The first one is a qualitative method mainly based on a heuristic assessment and the second is a quantitative approach taking into account the occurrence probability of severe negative events. Even though the qualitative approach is not consistent with the definition of risk used in the quantitative procedure, we proved that mCRHRS ratings are comparable with risk values, expressed as probability of death of at least one occupant of a vehicle (fatal accident) exposed to the rockfall hazard per year
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
Photochemical direct perfluoroalkylation of phenols
No full textA metal-free photochemical strategy for the direct aromatic perfluoroalkylation of phenols is reported. This operationally simple approach occurs at ambient temperature and under illumination by a fluorescent light bulb. The chemistry is driven by the ability of phenolate anions, transiently generated upon deprotonation of phenols, to directly reach an electronically excited state upon light absorption while successively triggering the formation of reactive radical species from perfluoroalkyl iodides. Preliminary mechanistic studies are reported
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
TIFS: A hybrid scheme integrating partitioned iterated function system and linear transforms
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