1,721,075 research outputs found
Prediction Models for Cardiac Risk Classification with Nuclear Cardiology Techniques
Full text linkRegression modeling strategies are increasingly used for the management of subjects with cardiovascular diseases as well as for decision-making of subjects without known disease but who are at risk of disease in the short- or long-term or during life span. Accurate individual risk assessment, taking in account clinical, laboratory, and imaging data is useful for choosing among prevention strategies and/or treatments. The value of nuclear cardiology techniques for risk stratification has been well documented. Many models have been proposed and are available for diagnostic and prognostic purposes and several statistical techniques are available for risk stratification. However, current approaches for prognostic modeling are not perfect and present limitations. This review analyzes some specific aspects related to prediction model development and validation
Prognostic Value of Stress Myocardial Perfusion Imaging in Asymptomatic Diabetic Patients
No full textAlthough there has been a marked decline in mortality due to coronary artery disease (CAD) in the overall population in the past three decades, reducing CAD mortality in patients with diabetes has proven exceptionally difficult. Several epidemiological studies have shown that diabetes is associated with a marked increase in the risk of CAD. The symptoms are not a reliable means of identifying patients at higher risk considering that angina is threefold less common in diabetics than in nondiabetics. The increasing prevalence of diabetes and the associated high cardiac risk raised the question as to the need to develop approaches to identify the diabetic patients at the highest risk of CAD. Stress myocardial perfusion single-photon emission computed tomography has taken a central role in the diagnosis, evaluation, and management of CAD in diabetic patients. This review focuses on the prognostic value of cardiac radionuclide imaging in asymptomatic diabetic patients. © 2014 Springer Science+Business Media New York
Betting on football: a model to predict match outcomes
No full textIn the context of sports betting, estimates of probabilities related to specific
events in a football match are quantities of deep interest. Starting from appropriate
marginal and conditional distributions, a joint distribution is introduced in
order to model the dependence between the number of goals scored by the two opposing
teams. This model allows to obtain estimates of probabilities for all the possible
match outcomes and, in so doing, to develop a betting strategy. An application
is presented in this paper: it shows encouraging results and highlights satisfactory
return in the long run
Usefulness of stress cardiac single-photon emission computed tomographic imaging late after percutaneous coronary intervention for assessing cardiac events and time to such events
No full textThis study assessed the predictors and temporal characteristics of cardiac risk in patients undergoing stress single-photon emission computed tomography (SPECT) after percutaneous coronary intervention (PCI). Stress SPECT was performed in 346 patients 12 to 18 months after PCI. Cardiac death and myocardial infarction were considered events. Cox proportional hazards analysis was used to identify predictors of events and parametric survival analysis to predict time to events. During follow-up (31 +/- 10 months), 17 events occurred (4.9% cumulative event rate). Prescan likelihood of ischemia and ischemia at SPECT were independent predictors of events (p or =2% risk of events were >48 months in those with low prescan likelihood of ischemia and >20 months in those with intermediate to high prescan likelihood. Ischemia at SPECT was associated with higher probability of failure accelerating over time. In conclusion, clinical variables and stress SPECT performed 12 to 18 months after PCI are useful to characterize risk of cardiac events and its temporal variation. Parametric survival models seem useful to estimate predicted time to risk and levels of risk at specific intervals after PCI
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
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