1,720,959 research outputs found
Heterogeneous platelet-activating factor (PAF) receptors and calcium increase in platelets and macrophages
No full textWe used the increase in cytosolic Ca2+ levels, [Ca2+]i, as a way to characterize PAF (platelet-activating factor, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) receptors in human platelets and rat and human macrophages. [Ca2+] was measured by means of the fluorescent probe fura-2/acetoxymethylester. PAF recognized heterogeneous receptors in human macrophages only (curve slope <1). The PAF antagonist SCH 37370 (1-acetyl-4(8-chloro-5,6-dihydro-11H-benzo[5.6]cyclohepta[1,2-b]pyridine -11-ylidine)piperidine) abolished [Ca2+]i elevation in human platelets, while in rat and human macrophages the maximal inhibition was 76% and 85%, respectively. On the contrary, the antagonist WEB 2086 (3-[4-(2-chlorophenyl)-9-methyl-6Hthieno[3,2-f] [1,2,4]triazolo-[4,3-a] [1,4]-diazepin-2-yl]-1-(4-morpholiny)-1-propanon, apafant) totally inhibited the effect of PAF in both platelets and macrophages. The WEB 2086 concentration-response curves had a slope <1 in the three cell types, indicating interaction with heterogeneous receptors. Accordingly, 3H-WEB 2086 bound to two different classes of sites. Both phases of [Ca2+]i elevation (influx or release) were equally affected by the antagonists. These data support the notions that: 1) PAF receptors are heterogeneous; 2) the two antagonists have a different selectivity toward the receptor subtypes: WEB 2086 recognizes two different receptors both in platelets and in macrophages, while SCH 37370 does not discriminate between receptor subtypes in platelets, and only interacts with one subtype in macrophages; and 3) both SCH 37370 and WEB 2086 display different potencies in rat and human macrophages
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
How to provide an alerting service on health topics for medical journalists selecting papers from scientific journals
No full textHealth topics for medical journalist for a correct information to general publi
Recommendations for health reporting : proposal of a working paper
No full textObjective: Media are a main source of medical information for the public, as well as for decision makers. This scenario demands a good selection of stories and correct medical reporting.
Design: Our study aimed to analyze if journalistic guidelines or similar documents were already available and whether they provided satisfactory advice for appropriate communication in the field, and to detail recommendations which could become a reference working document.
Methodology: Sources for this paper were obtained from PubMed and from websites ( and related links) of organizations known to be working in the area of health reporting. Documents providing recommendations for the activity were analyzed and compared through a scheme including nine macro-categories relevant to the selection, verification and building of the story, considering scientific and journalistic issues. The scheme was derived from the most complete document. We then compiled a comprehensive list of recommendations merging the contents of the documents considered and our professional experience.
Results: Nine existing guidelines and similar documents representing the worldwide situation were compared. All the documents examined provided interesting indications. Some of these indications shared the basic principles of mainstream journalism ( reliability and independence of sources); others were more specific, such as the understanding of the scientific method and its jargon, the need to avoid extrapolations and to understand the difference between in vitro and animal studies and clinical trials, statistical parameters, and so on. Most of the topics specific for health communication are concepts which can be grasped only with an adequate scientific background and continuing education. The nature and level of the details provided by these documents vary considerably and in most cases can be fully understood only by experienced journalists with a relevant background.
Discussion: Our proposal provides a useful tool listing nearly 70 recommendations ranging from the education of journalists, to all the aspects of selection, understanding and translating of medical and drug information deriving from scientific reports. It is intended for a journalist with a biomedical background, and therefore highlights critical issues without providing detailed descriptions. The proposal endeavors to answer to the main criticisms of medical journalism, particularly the use of sources, the verification of clinical value, the need to follow up on the story. Our work focuses on the prerequisite for a medical journalist to acquire the knowledge that enables him to assess the results of pharmacological and medical research in order to accurately and reliably convey his message to a lay reader. The strength of our working paper derives from the preliminary 'benchmarking' of existing documents, as suggested in the literature, but even more so from the concerted effort of the authors, who represent the key stakeholders of the system ( researchers, academic teachers, medical journalists and publishers).
Conclusion: Our work identifies the major issues entailed in correct health reporting, and constitutes a step forward in overcoming existing barriers between scientists and journalists. The aim is to encourage the mediation of 'public-centred' information, which limits the false hopes and expectations that may arise due to communication problems between the two worlds
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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