1,721,109 research outputs found
GAS DAMPING AT LOW PRESSURES IN MICROMACHINED RESONATORS
No full textA fundamental loss mechanism in microresonators at low vacuum levels is the energy
transfer from the resonating mass to the surrounding gas. Both continuum models (based on
Navier-Stokes equations) and molecular models (based on the microscopic motion of the
gas molecules) have been proposed to explain experimental damping data. In this work, we
present measurements of quality factor and damping factor, extracted with a novel
measurement method, for several micromachined resonators, and we compare them with ..
Modeling of capacitive coupling in micromirror arrays by means of Schwarz-Christoffel conformal mapping
No full textComputational fluid dynamics of the ascending aorta before the onset of type A aortic dissection
No full textWe performed a pre-dissection computational fluid analysis of an ascending aortic aneurysm associated with unicuspid aortic valve. The analysis showed an abnormal helical flow pattern inside the aneurysm and an increased wall stress on the right postero-lateral wall of the ascending aorta. These values were largely higher than the theoretical cut-off for aortic wall dissection, their topographic distribution followed the intimal tear site as subsequently diagnosed by computed tomography scan and confirmed during the operation for dissection repair
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
A Computationally Efficient Technique for the Optimization of Two Stage CMOS Operational Amplifiers
No full textIn this paper a mixed numerical-analytical method for optimizing the design of two stage operational amplifiers is presented. The main difference with respect to similar approaches is the elimination of as much as possible degrees of freedom of the problem by means of analytical and practical considerations. A built-in MATLAB function has been used to carry out the numerical optimization. The method has been applied to a simple two stage CMOS operational amplifier topology and the results have been verified by means of electrical simulations
Telemedicine-assisted treatment of patients with intracerebral hemorrhage
No full textObject. Telemedicine provides a new approach to improve stroke care in community settings, delivering acute
stroke expertise to hospitals in rural areas. Given the controversies in many aspects of the treatment of intracerebral
hemorrhage (ICH) and the lack of guidelines, a prompt neurosurgical second opinion may facilitate the treatment of
patients with ICH. Here, the authors’ 8-year experience with the use of telemedicine in the management of ICH is
reported.
Methods. The medical records of patients with ICH treated through a telemedicine system in the district of
Messina, Italy, between June 2003 and June 2011 were retrospectively reviewed. Neuroradiological and clinical
data for patients were transmitted through a high-technology “hub-and-spoke” telemedicine network. Neurosurgical
teleconsulting (at the hub) was available for 7 peripheral hospitals (spokes) serving about 700,000 people. The authors analyzed 1) the time between peripheral hospital admission and the specialized second opinion consultation, 2)
primary and secondary transfers to the authors’ neurosurgery department, and 3) the treatments (surgical or medical)
of patients transferred to the hub.
Results. The telemedicine network was used to treat more than 2800 patients, 733 with ICH. A neurosurgical
consultation was provided in 38 minutes versus 160 minutes for a consultation without telemedicine. One hundred
seventy-six (24%) of 733 patients were primarily transferred to the hub. Ninety-five patients (13%) underwent surgical treatment. The remaining 81 patients (11%) underwent neurointensive care. Eight (1.4%) of 557 patients treated
at the spokes needed a secondary transfer for surgical treatment because of a worsening clinical condition and/or CT
findings. Considering secondary and inappropriate transfers, the interpretation of data was correct in 96.5% of cases.
Conclusions. Telemedicine allowed rapid visualization of neuroradiological and clinical data, providing neurosurgical expertise to community hospitals on demand and within minutes. It allowed the treatment of patients at
peripheral hospitals and optimized resources. A small percentage of patients treated at the peripheral hospitals had
secondary deterioration. Telemedicine allowed fast patient transfer when necessary and provided improved accuracy
in patient car
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