1,720,989 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
Comparison of the prognostic value of the stress-recovery index versus standard electrocardiographic criteria in patients with a negative exercise electrocardiogram
No full textTo verify whether the stress recovery index (SRI) improves risk stratification in patients with a negative exercise electrocardiogram (ECG) using standard criteria, the SRI was derived in 708 consecutive patients with a negative exercise ECG. All-cause mortality and the combination of death or nonfatal myocardial infarction were target end points. The individual effect of clinical and exercise testing data on outcome was evaluated using Cox regression analysis with separate models for each group of variables. Model validation was performed using bootstrap adjusted by degree of optimism in estimates. Survival analysis was performed using a product-limit Kaplan-Meier method. During a 37-month follow-up, 22 deaths and 40 nonfatal acute coronary syndromes occurred. After adjusting for confounding variables, age (hazard ratio 1.62, 95% confidence interval [CI] 1.14 to 2.31 for interquartile difference), hypertension (hazard ratio 1.74, 95% CI 1.04 to 2.89), and SRI (hazard ratio 0.75, 95% CI 0.65 to 0.86 for interquartile difference) were predictive of death or nonfatal myocardial infarction. Moreover, SRI increased the prognostic power of the model on top of clinical and exercise testing variables and provided significant discrimination of survival. In conclusion, the SRI may help refine the prognostic stratification of patients with a negative exercise test result using standard electrocardiographic criteria
Safety and feasibility of dobutamine and dipyridamole stress echocardiography in hypertensive patients
No full textTo establish whether safety and feasibility of dobutamine and dipyridamole stress echocardiography are affected by history of hypertension
Stress echocardiography for risk stratification of diabetic patients with known or suspected coronary artery disease
No full textCoronary artery disease (CAD) is a leading cause of mortality and morbidity in diabetic patients; therefore, their risk stratification is a relevant issue. Because exercise tolerance is frequently impaired in these patients, pharmacological stress echocardiography (SE) has been suggested as a valuable alternative. Our aim was to evaluate the prognostic value of this technique in diabetic patients with known or suspected CAD
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
The Stress-Recovery Index for the risk stratification of women with typical chest pain
No full textAIM:
To prospectively assess the prognostic value of the Stress-Recovery Index (SRI) in women with typical chest pain.
METHODS:
165 women without known coronary artery disease, who complained of typical chest pain, were exercise tested and prospectively followed-up for the occurrence of cardiac death and nonfatal myocardial infarction. SRI, defined as the difference in absolute values between the area of heart rate-adjusted ST-segment depression during exercise and recovery, was derived in all. Clinical data, resting ejection fraction, and exercise testing data were entered into a sequential Cox's model; SRI was entered last. Model validation was performed by bootstrap adjusted by the degree of optimism in estimates. Survival curves were set up using Kaplan-Meier method and compared by the log-rank test.
RESULTS:
During a median follow-up time of 42 months, 19 events (14 cardiac deaths and 5 nonfatal myocardial infarction) were observed. Age (hazard ratio 3.58, 95% CI 0.87-15) and SRI (hazard ratio 0.62, 95% CI 0.42-0.92) were multivariate predictors of outcome. However, the addition of SRI increased the prognostic power of the model on top of clinical and exercise testing variables, as demonstrated by the significant (p=0.003) increase of the area under the ROC curve of the risk function. Survival analysis showed ascending SRI quartiles to identify a significant (p=0.005) increase in event-free survival.
CONCLUSIONS:
SRI is of value in predicting outcome of women with typical chest pain and provides additional prognostic information on the top of clinical and standard exercise testing data
Myocardial Doppler at rest for the identification of myocardial viability
No full textEchocardiography may permit the detection of a nonviable myocardium. The aim of this study was to test if resting pulsed wave-tissue Doppler imaging (PW-TDI) might yield additional markers
Stress echocardiography for risk stratification of patients with chest pain and normal or slightly narrowed coronary arteries
No full textOne hundred twenty-five patients (60 +/- 10 years old, 60 women) with known (35, previous myocardial infarction) or suspected (90) coronary artery disease (CAD) and no more than 50% coronary stenoses underwent pharmacologic (48 dipyridamole and 77 dobutamine) stress echocardiography (SE) and prospective follow-up (36 +/- 22 months) for cardiac death, nonfatal infarction, and unstable angina. The ability of clinical and SE variables to predict the outcome was assessed by the Cox model. A significant increase in the global chi-square of the model indicated an incremental prognostic value. Nine events occurred: 2 fatal and 5 nonfatal infarctions and 2 hospitalizations for unstable angina. Hypertension, positive SE, and peak wall motion score index were multivariate predictors of outcome, but SE provided an 87.5% increase in the global chi-square (P <.001). Patients with positive SE had a significantly lower event-free survival compared with those with negative SE. Therefore, we conclude that SE provides incremental prognostic information in patients with chest pain without critical coronary artery disease
- …
