1,721,004 research outputs found
Effects of Various Stripping Techniques on Surface Enamel
No full textAgreat deal of clinical evidence and reporteddata suggest that the burs used to reduceinterproximal enamel create furrows and scratchesthat can lead to carious lesions, periodontaldisease, and oversensitivity to extreme temperatures. 1Studies conducted on fragments of intraoralenamel have shown that the size and particularlythe depth of these furrows can have a significanteffect on remineralization and thus onthe formation of demineralizing lesions. 2Themore numerous and deep the lesions, the higherthe risk that they will be carious.The present study was intended to assesssurface changes in enamel caused by treatmentwith various stripping and finishing techniques
Ballistic accretion on a point seed
Full text linkWe carefully discuss the two-dimensional ballistic aggregation process. Studying the microscopic discrete process, we theoretically derive the probability density function describing the single-particle accretion. Using this function, we describe the properties of the “fan”, obtained for ballistic aggregation on the single seed, and we predict its mean density and its opening angle. We discuss the shadowing effect on a microscopic scale, between the single particles and, on a larger scale, between grown structures, deriving the columnar microstructure direction law. Comparisons with numerical experiments are shown
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
Bus crash risk evaluation: An adjusted framework and its application in a real network
Full text linkGreater attention to bus safety can lead to relevant benefits for public transport companies in terms of higher service performance, reliability, and lower insurance costs. Therefore, measuring the crash risk on bus routes provides an opportunity to improve the safety performance of transit operators. Previous research has explored the effects of many factors regarding the frequency and severity of bus crashes, whereas only a handful of studies have defined some crash risk indexes. Conversely, to the best of our knowledge, almost no research has been done regarding the crash risk in the bus transit network that integrates frequency, severity, and the exposure factors. This paper proposes a new framework to assess the crash risk for each transit bus route by the integration of safety factors, prediction models and risk methods. More precisely, this framework identifies several safety factors and specifies the risk components in terms of frequency, severity and exposure factors that may affect bus crashes. Then, it models their relationships to build a bus crash risk function. Lastly, according to the values returned by the previous function, the crash risk for each route is computed and a safety performance ranking for each route is provided. The feasibility of this framework is demonstrated in a real case study by using bus crash data provided by a mid-sized Italian bus operator. The findings show that transit managers could implement this framework in a road traffic safety management system to evaluate the risk of crashes on routes, monitor the safety performance of each route and qualify each route according to recent safety norms
Refining a crash risk framework for urban bus safety assessment: Evidence from Sardinia (Italy)
No full textAssessing the crash risk on bus routes would be pivotal to increasing the transit system safety. All past studies largely focused on the proposal of some crash risk indexes, and only one (recent) research has computed the bus crash risk in transit services by developing a bivariate (frequency and severity) risk model. Conversely, as far as the authors’ knowledge, no research attempted to quantify the probability of bus crash occurrence as a risk component and present results by geographic information systems. This study covers these gaps by refining an existing framework to better adhere to the original and well-accepted definition of risk. Specifically, it models the bus crash risk on (parts of) routes as a function of the probability of having a crash, the related severity, and exposure terms. Next, (parts of) routes are ranked according to the risk value and classified by a multilevel scale, to show those with the highest risk. Experiments highlight the viability of this framework using 3000+ raw bus crash data records. The results are synthesised by straightforward charts and maps. This framework helps support public transport companies in enhancing safety performance because it could be implemented in a transit safety managerial system for monitoring and certification purposes according to safety norms and EU directives
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