1,720,971 research outputs found
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
Dynamic validation of a masonry arch bridge seismic retrofit
No full textThis paper presents the dynamic characterization of a retrofitted masonry arch bridge. The Gresal Bridge, located in a seismic area in the North-East of Italy, was rated highly vulnerable to seismic hazard, mostly due to the slenderness of its high piers. A retrofit intervention has been carried out, and a new r.c. slab has been built under the pavement, anchored to the piers with high strength vertical ties and restrained at the abutments, to create a new resistance arrangement withstanding inertial forces. The dynamic behaviour has been initially assessed with numerical models comparing the response of the bridge before and after the repair, and has subsequently been tested by the Output-Only technique to detect the
variation of the modal response induced by the strengthening intervention. The dynamic tests have shown the retrofitted structure to be less rigid than expected and, after calibration, a good agreement was found between the numerical frequencies and the experimental records captured on the retrofitted bridge
Mutagenic activity of carbon black dyes used in the leather industry
No full textSeven carbon black pastes used as commercial leather dyes were tested for their mutagenicity in the Salmonella/microsome test (TA98 and TA100 strains). All the samples assayed either directly or after extraction with a 30-min sonication in benzene were devoid of mutagenicity both in the presence and absence of a metabolic activation preparation. After a 48-h extraction with boiling toluene in a Soxhlet apparatus, four samples were mutagenic in TA98 strain in the presence of S9 mix. The activity ranged from 1.3 to 9.6 induced revertants/mg equivalent of extract. A weak direct mutagenic activity in strain TA98 was shown by one extract. Polycyclic aromatic hydrocarbons (PAH) were determined in the toluene extracts by high resolution gas chromatography/mass spectrometry. The presence of PAH could explain the mutagenicity of only one sample (8.79 micrograms of total PAH/100 mg equivalents of extract), while low or undetectable levels of PAH were found in the other mutagenic extracts. The mutagenic activity was evident only after a vigorous extraction process, thus a low bioavailability of the mutagens present in these compounds is suggested
Application to an urban bridge stock of a prioritization procedure based on seismic assessment compared with the novel Italian guidelines
Full text linkThe challenge of large-stock maintenance with limited budget is faced by administrations in charge which need tools for management and intervention prioritization. This need is especially perceived for bridges which are strategic structures and represent crucial elements in roadway networks. Since 2016, a combined prioritization procedure has been applied to the bridge stock of the Municipality of Padova (Italy) to assess both the condition state, accounting for degradation, and the seismic vulnerability. The proposed methodology evaluates the level of degradation through visual inspections and type-specific forms for the defect survey, while the seismic vulnerability is assessed by means of fragility curves previously obtained by the authors for typical Italian bridges. This contribution focuses on the application of the seismic-based prioritization. The identification of the bridge typologies which appeared to be more seismically fragile is presented, comparing this aspect with results from the recently issued novel Italian Guidelines for the management of existing bridges
A simplified procedure for seismic vulnerability assessment of railway masonry arch bridges
No full textIn this work a comprehensive parametric study was carried out to assess the seismic capacity of masonry arch bridges by limit analysis. The kinematic method was applied to evaluate structural capacity under horizontal seismic forces which may affect the structure in longitudinal and transverse direction and activate local or overall collapse mechanisms.
Horizontal accelerations triggering the collapse mechanism were calculated, and iso-acceleration envelope curves, representing the limit acceleration of the bridge as a function of simple geometric parameters, were derived.
These graphs supply a direct tabular procedure for preliminary seismic assessment of single-and multi-span masonry bridges
Masonry arch bridges in the Italian railway engineering experience: state of condition, static reliability, seismic verification and retrofit strategies
No full textMasonry arch bridges still represent a crucial element of the railway transportation network across Europe. Many of them are part of the historical heritage of the XIXth century, and are underdesigned for actual service conditions. Due to the intrinsic weakness of some structural components, to deterioration phenomena and to the updating of structural codes, masonry arched structures show often inadequate performance considering the static and seismic requirements of current codes. Reliable methods are thus required for the assessment of static and seismic reliability, and to prioritize retrofit interventions. Simplified procedures shall be used for large-scale planning: for this purpose the kinematic method, based on an adaptation of limit design for masonry structures, has proved to be a conceptually simple and robust procedure to verify the safety of masonry arches. Standard strategies should be finally proposed for the rehabilitation of arch bridges, taking into account to this end the original design and construction system and limiting to the minimum the required retrofit interventions
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
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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