1,721,533 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
New frontiers in the feasibility of optical coherence tomography in carotid arteries
No full textComment on:
Frequency-domain optical coherence tomography assessment of human carotid atherosclerosis using saline flush for blood clearance without balloon occlusion. [AJNR Am J Neuroradiol. 2013
Minimally invasive or conventional aorto-bifemoral by-pass. A randomised study
No full textAbstractIntroduction: open transperitoneal aorto-bifemoral by-pass is still associated with a relatively high morbidity and mortality. To decrease this surgical stress, minimally invasive direct aortic surgery (MIDAS) was developed, utilizing a minilaparotomy and a retroperitoneal approach to the aorta. Objectives: to compare in a randomised controlled trial whether mortality and morbidity could be reduced with MIDAS. Methods: from October 1997 to September 2000, 300 patients were randomised to either MIDAS (n = 150) or conventional aorto-bifemoral by-pass surgery (n = 150). Results: the perioperative (30 days) mortality (2.6%), was equal in both groups. MIDAS were significantly reduced length of hospital stay (3.1 days), and pulmonary dysfunction. Conclusions: MIDAS reduced trauma and pain, which resulted in a shorter hospital stay, and a reduction in costs
The long journey of acute limb ischemia management: from the disappointing observation of a medical student to precision medicine and the tailored endovascular treatment
No full textDynamical cosmological constant
Full text linkThe dynamical realization of the equation of state p & thorn; rho = 0 is studied. A nonpathological dynamics for the perturbations of such a system mimicking a dynamical cosmological constant (DCC) requires to go beyond the perfect fluid paradigm. It is shown that an anisotropic stress must be always present. The Hamiltonian of the system in isolation resembles the one of a Pais-Uhlenbeck oscillator and linear stability requires that it cannot be positive definite. The dynamics of linear cosmological perturbations in a DCC dominated Universe is studied in detail showing that when DCC is minimally coupled to gravity no dramatic instability is present. In contrast to what happens in a cosmological constant dominated Universe, the nonrelativistic matter contrast is no longer constant and exhibits an oscillator behavior at small scales while it grows weakly at large scales. In the gravitational waves sector, at small scales, the amplitude is still suppressed as the inverse power of the scale factor while it grows logarithmically at large scales. Also the vector modes propagate, though no growing mode is found
Development of GaN - bases three-phase Grid- Tie Inverter
No full textWide band gap (WBG) semiconductor devices have been widely concerned due to their superior performance over conventional Si power devices. They are expected to improve the power converters' efficiency and density. The main objective of this paper is to present the design of a three-phase Ga-based inverter with a particular focus on the feasibility of GaN applications in PV inverters, reliability, and efficiency. PCB boards are designed and tested for the control and power circuits, and the advantage of fibre optic connection for the PWM transmission is highlighted. The methodology covers the main steps of PV inverter design and design considerations. The key parameters and experimental results are presented. The power density is 60 W/inch3, and the peak efficiency is 96% at 5kWload
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