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Clinical outcomes of the AdaptResponse trial – Authors' reply
No full textwhether the position of the left ventricular pacing is necessarily optimal. The left ventricular pacing lead position is important in relation to the clinical and mechanical response to CRT. Both lead placement, guided by cardiac imaging, 2 and positioning, determined by the electrical latency in intracardiac electrograms, 3 effectively improve the CRT response. The paced morphology of the electrograms recorded by the CRT device can reveal the effectiveness of the pacing. A highly effective CRT pacing rate is associated with a high prevalence of CRT responders and low risk of hospitalisation for heart failure. 4 We would like to know how the investigators determined the position of their left ventricular pacing leads for an effective adaptive CRT response. Alternatively, the investigators could have had the option of using multipolar leads, such as quadripolar leads, which do not require optimal lead positioning. Quadripolar leads are known to be associated with lower allcause mortality than conventional bipolar leads. 5 We declare no competing interests.Medtronic; Novo Nordisc; Bayer; Boehringer Ingelheim; Servier; Vifor;Cardior; Impulse Dynamics; EU; Biotronik; Medtronic Japan; Pfizer;Biotronik Japan; Bristol Myers Squibb; Medtronic; Boston Scientifi
Revisión de varios métodos para modelar tiempo a múltiples eventos por sujeto: modelamiento de tiempo a hospitalizaciones y muerte
Full text linkAlgunos ensayos clínicos para estudiar el efecto de nuevos tratamientos en pacientes con insuficiencia cardiaca (IC) se basan en la evaluación de hospitalizaciones relacionadas con IC y muerte. Frecuentemente el análisis se enfoca en el tiempo a la primera ocurrencia de alguno de estos dos desenlaces. Este tipo de análisis ignora importantes eventos como nuevas hospitalizaciones relacionadas con IC, que permiten una mejor descripción y compresión del proceso de recuperación de estos pacientes. En este trabajo se describen y exploran varias estrategias para el análisis de tiempo a repetidas hospitalizaciones relacionadas con IC y tiempo a la muerte. Se estudian modelos marginales para incorporar la correlación intra-sujeto y riesgos competitivos propios de este tipo de ensayos clínicos. Finalmente, se recomienda un modelo multi-estado como una estrategia sencilla y flexible que incorpora elementos importantes en el análisis de hospitalizaciones relacionadas con IC y muerte, y a la vez extiende características relevantes de los modelos de Andersen and amp; Gill (1982), Wei et al. (1989) and Prentice et al. (1981).During the disease-recovery process of many diseases, such as in Heart Failure (HF), often more than one type of event plays a role. Some clinical trials use the combined endpoint of death and a secondary event; for instance, HF-related hospitalizations. This is often analyzed with time-to-first-event survival analysis which ignores possible subsequent events, such as several HF-related hospitalizations. Accounting for multiple events provides more detailed information on the disease-control process, and allows a more precise understanding of the prognosis of patients. In this paper we explore and illustrate several modelling strategies to study time to repeated events of disease-related hospitalizations and death per subject. Marginal models are revised in order to account for intra-subject correlation and competing risks. Finally, we recommend a Multi-state model which allows a flexible modelling strategy that incorporates important features in the analysis of HF-related hospitalizations and death, and at the same time extends relevant characteristics of the Andersen and amp; Gill (1982), Wei et al. (1989) and Prentice et al. (1981) models
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
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