1,720,997 research outputs found
An integrated approach using high time-resolved tools to study the origin of aerosols
Full text linkLong-range transport of natural and/or anthropogenic particles can contribute significantly to PM10 and PM2.5 concentrations and some European cities often fail to comply with PM daily limit values due to the additional impact of particles from remote sources. For this reason, reliable methodologies to identify long-range transport (LRT) events would be useful to better understand air pollution phenomena and support proper decision-making.This study explores the potential of an integrated and high time-resolved monitoring approach for the identification and characterization of local, regional and long-range transport events of high PM. In particular, the goal of this work was also the identification of time-limited event. For this purpose, a high time-resolved monitoring campaign was carried out at an urban background site in Bari (southern Italy) for about 20days (1st-20th October 2011). The integration of collected data as the hourly measurements of inorganic ions in PM2.5 and their gas precursors and of the natural radioactivity, in addition to the analyses of aerosol maps and hourly back trajectories (BT), provided useful information for the identification and chemical characterization of local sources and trans-boundary intrusions. Non-sea salt (nss) sulfate levels were found to increase when air masses came from northeastern Europe and higher dispersive conditions of the atmosphere were detected. Instead, higher nitrate and lower nss-sulfate concentrations were registered in correspondence with air mass stagnation and attributed to local traffic source. In some cases, combinations of local and trans-boundary sources were observed. Finally, statistical investigations such as the principal component analysis (PCA) applied on hourly ion concentrations and the cluster analyses, the Potential Source Contribution Function (PSCF) and the Concentration Weighted Trajectory (CWT) models computed on hourly back-trajectories enabled to complete a cognitive framework and confirm the influence of aerosol transported from heavily polluted areas on the receptor site
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
Reliability of Percutaneous Pulmonary Vent and Coronary Sinus Cardioplegia in the Setting of Minimally Invasive Aortic Valve Replacement: A Single-Center Experience
No full textObjectives Evaluating the efficacy of 2 new percutaneous devices specifically designed to be placed through the right internal jugular vein, therefore named “necklines,” for achieving retrograde cardioplegia and pulmonary venting in the setting of minimally invasive aortic valve replacement (MIAVR). Design Case series. Setting University-affiliated private hospital. Participants Patients undergoing MIAVR. Interventions Necklines were placed by the anesthesiologist using transesophageal electrocardiography, with pressure guidance before the surgical procedure was initiated. Measurements and Main Results The records of 51 consecutive patients who underwent MIAVR with necklines placement were reviewed retrospectively. The access for MIAVR was through either a J-hemisternotomy or a right anterior thoracotomy. The efficacy of the 2 catheters, successful placement rate, time needed to deploy catheters, and perioperative complications were recorded. Necklines were placed successfully in all patients in 23±13 minutes. A total of 110 doses of retrograde cardioplegia were delivered at a mean flow rate of 173±35 mL/min and a mean pressure of 41±6 mmHg. The pulmonary catheter ensured venting of the heart that was graded by surgeons as “excellent” in 33 patients, “sufficient” in 12 patients, and “not adequate” in 2 patients. There were no major adverse events or deaths. Conclusions Necklines ensure effective retrograde cardioplegia and venting of the heart, provide optimal surgical vision and access during MIAVR, and allow surgeons to operate in an unobstructed surgical field. Nevertheless, additional studies are required to determine whether the use of necklines is associated with better outcomes than those with conventional methods
Percutaneous coronary sinus catheterization with the ProPlege catheter under transesophageal echocardiography and pressure guidance
No full textObjectives Percutaneous catheterization of the coronary sinus (CS) to enable the administration of retrograde cardioplegia may play an important role in minimally invasive cardiac surgery. A new specially designed device (ProPlege; Edwards Lifesciences, Irvine, CA) is described that can be placed under transesophageal echocardiography (TEE) and pressure guidance with a high rate of success and low rate of complications. Design Case series. Setting A university-affiliated private hospital. Participants Patients undergoing minimally invasive cardiac surgery. Interventions The ProPlege device was placed under TEE and pressure guidance only. Measurements and Main Results Records of 70 patients managed with ProPlege were reviewed and analyzed. Successful placement was attained in 69 patients (98.6%) as confirmed by the ventricularization of the CS pressure curve and TEE images. Direct imaging of the ProPlege tip was possible in 34 patients (49.2%). The capacity to generate a CS pressure>30 mmHg during retrograde cardioplegia administration at a flow>150 mL/min was obtained in 64 patients; ProPlege displacement occurred in 5 cases (7.2%). Successful retrograde cardioplegia was delivered in 91.4% of cases. No CS perforation or other injuries to the right heart were noted at intraoperative TEE or direct surgical inspection. Conclusions Percutaneous CS catheterization with ProPlege was performed with a high rate of success for positioning and low complication rate using TEE and pressure guidance only. Further studies are needed to more accurately determine complication rates and to establish the possible complementary role of fluoroscopy
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
Determination of Relative Configuration in Organic Compounds by NMR Spectroscopy and Computational Methods.
No full textN
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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