1,721,089 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
Polynomial conjunctive query rewriting under unary inclusion dependencies
Full text linkOntology-based data access (OBDA) is widely accepted as an important ingredient of the new generation of information systems. In the OBDA paradigm, potentially incomplete relational data is enriched by means of ontologies, representing intensional knowledge of the application domain. We consider the problem of conjunctive query answering in OBDA. Certain ontology languages have been identified as FO-rewritable (e.g., DL-Lite and sticky-join sets of TGDs), which means that the ontology can be incorporated into the user's query, thus reducing OBDA to standard relational query evaluation. However, all known query rewriting techniques produce queries that are exponentially large in the size of the user's query, which can be a serious issue for standard relational database engines. In this paper, we present a polynomial query rewriting for conjunctive queries under unary inclusion dependencies. On
the other hand, we show that binary inclusion dependencies do not admit
polynomial query rewriting algorithms
Le metodologie di scavo
No full textUn volume che presenta al grande pubblico le più recenti scoperte scientifiche di un sito chiave del Quaternario mediterraneo: Grotta Romanelli (Castro, Lecce). Le attività di scavo archeologico sono riprese dal 2015 a cura di Sapienza Università di Roma
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
Le metodologie di scavo
No full textUn volume che presenta al grande pubblico le più recenti scoperte scientifiche di un sito chiave del Quaternario mediterraneo: Grotta Romanelli (Castro, Lecce). Le attività di scavo archeologico sono riprese dal 2015 a cura di Sapienza Università di Rom
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
Effects of periodate-oxidized ribonucleotides on tumor cell growth
No full textWe have studied the effects of periodate-oxidized ribonucleotides on the in-vitro cell proliferation of human myleoid leukemia K562, T-leukemic Jurkat, promyelocytic HL60 and transformed chinese hamster FH06T1-1 cell lines. oATP inhibits 50% at 5-20 microM, oGTP, oCTP and oUTP only at higher than 100 microM. Different cell lines are differentially affected. oADP, oAMP and o-adenosine were also found effective, even with a different efficiency
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