1,720,984 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
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
Synthesis of 1,2-benzisothiazolyloxypropanolamine derivatives and investigation of their activity at β-adrenoceptors
No full textThe synthesis of 3-methoxy-1,2-benzisothiazole derivatives, substituted in position 5- (compounds 1–7) or 7- (compounds 8–14), with oxypropanolaminic side chains and the pharmacological investigation on their activity at β-adrenoceptors are described. Compounds were prepared in an attempt to explore the ability of the benzisothiazole ring to interact with the β-adrenoceptor site and to establish whether oxypropanolaminic derivatives recognise the β3-adrenoceptor subtype. All the products were tested on rat atria, bladder and small intestine, which preferentially (but not exclusively) express β1-, β2- and β3-adrenoceptors, respectively. When compared with the reference, non-specific, β-adrenoceptor agonist isoprenaline, the products tested did not show any consistent β-adrenoceptor agonistic activity in the different models. Most compounds relaxed smooth muscle preparations, but such effect was resistant to the blockade by propranolol (1 μmol/l), ICI 118,551 (1 μmol/l) or bupranolol (1–10 μmol/l), thus excluding that the spasmolytic effect involves any β-adrenoceptors. When tested as antagonists, some of these products showed a concentration-dependent attenuation of the isoprenaline-induced effects in rat atria, without affecting β-adrenoceptor-mediated relaxation in smooth muscle. These data confirm the ability of the benzisothiazole ring to interact with β-adrenoceptors, but the substitution in 5- or 7-positions with oxypropanolaminic groups does not generate compounds endowed with specific activity at β3-adrenoceptors. Conversely, most of these compounds behave as (specific) antagonists at β1- (cardiac) adrenoceptors. At the maximum concentrations tested (1–100 μmol/l), these compounds also exert direct spasmolytic and negative chronotropic effects, which could be related to a blockade of Ca2+-dependent mechanisms at an intracellular level and/or an anaesthetic-like activity at plasma membranes
Attribute-Based Communication over Pub/Sub: Transactional Coordination for Smart Systems
No full textIoT and smart systems frequently rely on publish-subscribe (pub/sub) middlewares like MQTT or DDS. However, current coordination solutions often lack formal rigour, posing risks in mission-critical applications, or suffer from excessive complexity, hindering practical deployment and increasing the likelihood of errors. This paper addresses these challenges by integrating AbU, a recently introduced formal model based on Event-Condition-Action (ECA) rules and attribute-based communication, with standard pub/sub middlewares. We present a synchronization protocol that leverages pub/sub primitives to implement AbU’s transactional communication semantics. We prove the correctness of this protocol, demonstrating that it accurately reflects the underlying system dynamics. This integration of a formal ECA-based programming model with pub/sub offers a compelling balance between rigorous guarantees and practical applicability for coordinating IoT and smart systems
Abstract Interpretation based Verification of Logic Programs
No full textThis paper is an overview of our results on the application of abstract interpretation concepts to various problems related to the verification of logic programs. These include the systematic design of semantics modeling various proof methods and the characterization of assertions as abstract domains. We derive an assertion based verification method and we show two instances based on different assertion languages: a decidable assertion language and CLP used as an assertion language
Logic programs as specifications in the inductive verification of logic programs
No full textIn this paper we define a new verification method based on an assertion language able to express properties defined by the user through a logic program. We first apply the verification framework defined in another paper of ours to derive sufficient inductive conditions to prove partial correctness. Then we show how the resulting conditions can be proved using program transformation techniques
Benzisothiazoles and β-adrenoceptors: Synthesis and pharmacological investigation of novel propanolamine and oxypropanolamine derivatives in isolated rat tissues
No full textIn an attempt to examine the ability of benzisothiazole-based drugs to interact with beta-adrenoceptors, a series of 1,2-benzisothiazole derivatives, which were substituted with various propanolamine or oxypropanolamine side chains in the 2 or 3 position, were synthesised and tested. The pharmacological activity of these compounds at the beta-adrenoceptors was examined using isolated rat atria and small intestinal segments, which preferentially express the beta1- and beta3-adrenoceptor-mediated responses, respectively. None of these products showed any beta-adrenoceptor agonistic activity. In contrast, the 2- and 3-substituted isopropyl, tert-butyl, benzyl, and piperonyl derivatives 2a-d and 3a-d elicited surmountable inhibition of the isoprenaline-induced chronotropic effects in the atria, suggesting competitive antagonism at the beta1-recognition site. The pA2 values revealed tert-butyl 3b and the isopropyl substituted piperonyl derivatives 3a to be the most effective. Remarkably, many of the 2-substituted propanolamines were less active than the corresponding 3-substituted oxypropanolamines. With the exception of compound 3b, none of these drugs antagonised the muscle relaxant activity of isoprenaline in the intestine, suggesting no effect on the beta3-adrenoceptors. These results confirm the ability of the benzisothiazole ring to interact with the beta-adrenoceptors, and demonstrate that 2-substitution with propanolamine or 3-substitution with oxypropanolamine groups yields compounds with preferential antagonistic activity at the cardiac beta1-adrenoceptors. The degree of antagonism depends strongly on both the nature of the substituent and its position on the benzisothiazole ring
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