1,722,662 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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Risk of Upper Gastrointestinal Bleeding and the Degree of Serotonin Reuptake Inhibition by antidepressant. A case control study
No full textBackground and objective: Selective serotonin reuptake inhibitor (SSRI) antidepressants can inhibit uptake of serotonin by platelets, and their use may predispose patients to bleeding. Case reports and observational studies from databases have suggested an association between the use of SSRIs and gastrointestinal bleeding. Their risk appears to be increased if they are concurrently used with aspirin (acetylsalicylic acid) or with other NSAIDs. With the aim of establishing the risk of major upper gastrointestinal bleeding associated with various groups of drugs, we performed a multicentre case-control study. We present the results related to the use of antidepressants by the degree of serotonin reuptake inhibition they
induce, the selectivity at monoamine transporters and the dose.
Methods: A population-based multicentre case-control study in 18 hospitals in
Spain and in Italy, including 2813 incident cases of upper gastrointestinal bleeding and 7193 matched controls. Regression analyses are based on 2783 cases and 7058 controls because of missing variable data. Odds ratios (ORs) of upper gastrointestinal bleeding for antidepressant drugs grouped by affinity for the serotonin transporter, selectivity and dose, with djustment for potential confounders were estimated.
Results: Overall, 84 (3.0%) cases and 160 (2.2%) controls had used a highaffinity serotonin reuptake inhibitor (SRI) antidepressant. Their use in the 7 days prior tothe index day was not associated with a substantially increased risk of upper gastrointestinal bleeding (OR = 1.24; 95% CI 0.88, 1.76). Forty-one (1.5%) cases and 26 (0.4%) controls had concurrently used a high-affinity SRI antidepressant and an NSAID. The OR of upper gastrointestinal bleeding among these concurrent users (8.32; 95% CI 4.69, 14.76) did not differ from that in users of NSAIDs only (7.82; 95% CI 6.79, 9.00). No significant association was found between the use of SSRIs and the risk of upper gastrointestinal bleeding, neither with the degree of affinity for the serotonin transporter, by the selectivity of each individual agent (101 cases [3.6%] vs 192 controls [2.7%]; OR = 1.23; 95% CI 0.90, 1.68), nor by dose.
Conclusions: The risk of upper gastrointestinal bleeding is not increased by the use of SRIs. An interaction with coadministered NSAIDs was not observed. If there is a risk associated to these drugs, it seems to be low and not an important cause of hospital admission due to upper gastrointestinal bleeding. However, additional studies may be warranted in subgroup populations at potentially increased risk of bleeding, such as older adults and men
Upper Gastrointestinal Bleeding Associated With Antiplatelet Drugs
No full textBackground
The risk of major upper gastrointestinal bleeding associated with various antiplatelet drugs and the protection conferred by gastroprotective agents are not well defined.
Aim
To estimate the risk of upper gastrointestinal bleeding associated with the use of antiplatelet drugs and its prevention by gastroprotective agents.
Methods
In a case-control study, we compared all cases of upper gastrointestinal bleeding from a gastric or duodenal lesion in patients over 18 years of age (2813 cases), with 7193 matched controls. Odds ratios of upper gastrointestinal bleeding for individual antiplatelet drugs with adjustment
for potential confounders were estimated.
Results
The individual risks of upper gastrointestinal bleeding were cardiovascular acetylsalicylic acid 4.0 (3.2–4.9), clopidogrel 2.3 (0.9–6.0), dipyridamole 0.9 (0.4–2.0), indobufen 3.8 (1.2–12.2), ticlopidine 3.1 (1.8–5.1) and triflusal 1.6 (0.9–2.7). Concomitant proton pump inhibitors decreased all risk estimates. For acetylsalicylic acid plus a proton pump inhibitor, the odds ratio was 1.1 (0.5–2.6). As a group, antiplatelet drugs accounted for 14.5% of all cases of upper gastrointestinal bleeding, i.e. 58 per million per year (334 per million per year among those older than 70 years).
Conclusions
The risk of upper gastrointestinal bleeding is substantially decreased by the concomitant use of proton pump inhibitors. The risk of acetylsalicylic acid plus a proton pump inhibitor seems lower than that of ticlopidine or clopidogrel
Upper gastrointestinal bleeding associated with the use of NSAIDs: newer versus older agents
No full textAIM:
The relative gastrointestinal toxicity of NSAIDs in normal clinical practice is unknown. The aim of this study was to estimate the risk of upper gastrointestinal bleeding associated with NSAIDs and analgesics, with special emphasis on those agents that have been introduced in recent years.
DESIGN:
Multicentre case-control study.
PATIENTS:
All incident community cases of upper gastrointestinal bleeding from a gastric or duodenal lesion in patients aged >18 years of age (4309 cases). After secondary exclusions, 2813 cases and 7193 matched controls were included in the analysis.
SETTING:
Eighteen hospitals in Spain and Italy with a total study experience of 10,734,897 person-years.
MAIN OUTCOME MEASURE:
Odds ratios of upper gastrointestinal bleeding for each drug, with adjustment for potential confounders. For each individual drug the reference category was defined as those not exposed to the drug.
RESULTS:
The incidence of upper gastrointestinal bleeding was 401.4 per million inhabitants aged >18 years. Thirty-eight percent of cases were attributable to NSAIDs. Individual risks for each NSAID were dose dependent. Ketorolac was associated with the highest risk estimate (24.7; 95% CI 8.0, 77.0). For newer NSAIDs, the risks were as follows: aceclofenac 1.4 (95% CI 0.6, 3.3), celecoxib 0.3 (95% CI 0.03, 4.1), dexketoprofen 4.9 (95% CI 1.7, 13.9), meloxicam 5.7 (95% CI 2.2, 15.0), nimesulide 3.2 (95% CI 1.9, 5.6) and rofecoxib 7.2 (95% CI 2.3, 23.0). The risk was significantly increased in patients with a history of peptic ulcer and/or upper gastrointestinal bleeding, and in those taking antiplatelet drugs.
CONCLUSIONS:
NSAID-induced upper gastrointestinal bleeding is a common cause of hospital admission. Apart from the patient's history of peptic ulcer, its risk depends on the particular drug and its dose, and on concomitant treatments. Our results do not confirm that greater selectivity for COX-2 confers less risk of upper gastrointestinal bleeding
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