1,720,971 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
Transient coronary artery occlusion during coronary sinus lead extraction: a possible cause of ischaemia and hypotension
No full textAppropriate 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
Validation of epicardial ventricular tachycardia criteria through left ventricular pacing in patients with non-ischaemic dilated cardiomyopathy: insights from a cardiac resynchronization therapy cohort
No full textHow Low Should We Go With Home Blood Pressure in Elderly Patients With Atrial Fibrillation?
No full textCardiac complications of COVID-19 vaccination: now we know more
No full textThe proliferation of good quality observational studies on the potential adverse effects of COVID-19 vaccination has greatly increased our knowledge on myocarditis and pericarditis, and also, more recently, on arterial hypertension. According to some recent studies, the incidence of a significant increase in blood pressure after COVID-19 vaccination is about 3.2% (95% CI: 1.62–6.21). The incidence of serious hypertensive emergencies or stage III hypertension has been reported as 0.6%. It is well known that the ‘spike protein’ of the Sars-CoV-2 virus, the synthesis of which is induced by vaccines, binds to ACE2 receptors, inducing their migration towards the inside of the cell. This would result in a lack of ACE2 activity on cell surfaces and therefore a relative deficiency of angiotensin1-7 with a relative excess of angiotensin II, which could explain, at least in part, the blood pressure increases. Regarding myo-pericarditis, there is evidence that the advantages of COVID-19 vaccination over non-vaccination remain preponderant in terms of prevented hospitalizations and serious complications of COVID-19, compared with the risk of developing myocarditis. In the age group most at risk of COVID-19 vaccine myocarditis (12–29 years), for every 100 000 vaccinated, compared to about four more cases of myocarditis we have 56 fewer hospitalizations, 13.8 admissions to intensive care and 0.6 fewer deaths. Several studies have shown that post vaccine myocarditis/pericarditis are generally short-lasting phenomena with favourable clinically course
Gli studi di non-inferiorità
No full textSuperiority trials are designed to test the hypothesis that a given diagnostic or therapeutic strategy is better than (i.e. “superior to”) placebo or an active control. Conversely, non-inferiority trials test the hypothesis that a newer (i.e. alternative) strategy is not “unacceptably worse” than a control (i.e. “traditional”, or “older”) strategy. Non-inferiority trials are increasingly conducted in clinical medicine more often when a “newer” strategy is supposed to offer a relevant advantage in terms other than clinical efficacy (i.e. better tolerability, less cost, simpler regimen, etc.) versus a “gold standard” traditional strategy. The principle underlying non-inferiority trials is that the above advantage justifies the preferential use of the newer strategy in the clinical practice even if the clinical efficacy of the “new” appears to be a bit worse than that of the “old”, albeit not unacceptably worse (i.e. not beyond a pre-specified value). The demonstration of non-inferiority requires that the confidence interval of the point estimate (e.g. the hazard ratio) does not cross a pre-specified limit. The definition of such pre-specified limit, the so called “non-inferiority margin”, is a pivotal point when planning non-inferiority trials. It denotes the maximally tolerated worse effect of the alternative strategy, compared with the traditional one, required to conclude that an alternative strategy is non-inferior to the traditional “gold standard”. The non-inferiority margin is derived from previous trials evaluating the efficacy of the traditional strategy vs placebo. We reviewed the principles and the practical aspects in the design and conduct of non-inferiority trials
Ventricular Preexcitation: An Anomalous Wave Interfering with the Ordered Ventricular Activation
No full textVentricular preexcitation is a depolarization of the ventricles that occurs before the conventional sequence, and the electrocardiogram is the specific test for diagnosis. A Kent bundle is the paradigm of ventricular preexcitation, and it is associated with short PR, wide QRS and delta wave. This finding is not always very evident, as it can have different degrees of pre-eccitazione; therefore great diagnostic care must be taken in this field. If not properly identified, the pattern of ventricular preexcitation may lead to an incorrect diagnosis. The methodology of precision electrocardiology is able to confront all these aspects
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