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Quantitative analysis of arsenic in mine tailing soils using double pulse-laser induced breakdown spectroscopy
No full textA double pulse-laser induced breakdown spectroscopy (DP-LIBS) was used to determine arsenic (As) concentration in 16 soil samples collected from 5 different mine tailing sites in Korea. We showed that the use of double pulse laser led to enhancements of signal intensity (by 13% on average) and signal-to-noise ratio of As emission lines (by 165% on average) with smaller relative standard deviation compared to single pulse laser approach. We believe this occurred because the second laser pulse in the rarefied atmosphere produced by the first pulse led to the increase of plasma temperature and Populations of exited levels. An internal standardization method using a Fe emission line provided a better correlation and sensitivity between As concentration and the DP-LIBS signal than any other elements used. The Fe was known as one of the major components in current soil samples, and its concentration varied not substantially. The As concentration determined by the DP-LIBS was compared with that obtained by atomic absorption spectrometry (AAS) to evaluate the current LIBS system. They are correlated with a correlation coefficient of 0.94. The As concentration by the DP-UBS was underestimated in the high concentration range (>1000 mg-As/kg). The loss of sensitivity that Occurred at high concentrations could be explained by self-absorption in the generated plasma. (C) 2009 Elsevier B.V. All rights reserved
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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Sachbericht zum Verwendungsnachweis - Abschlussbericht
Full text linkIm Rahmen des RUBIN-Verbundvorhabens SNiPoCC wurde ein Teilprojekt zur Entwicklung quantitativer, digital auswertbarer Point-of-Care-Testsysteme durchgeführt. Ziel war die methodische und technologische Weiterentwicklung von Lateral-Flow-Tests (LFTs) und papierbasierten analytischen Tests (PADs) für die veterinärmedizinische Diagnostik. Hierfür wurden eine Raman-basierte Linienfokus-Auslesetechnik mit homogenisiertem Strahlprofil sowie ein kamerabasiertes photometrisches Auslesesystem entwickelt. Zur Quantifizierung wurden automatisierte spektrale und bildanalytische Auswerteverfahren implementiert, einschließlich eines eigenständig entwickelten Softwaremoduls für nichtlineare (quadratische) Regression mit integrierter Fehlerrechnung. Ergänzend wurde die Eignung der Laser-Induced Breakdown Spectroscopy (LIBS) zur elementanalytischen Auswertung papierbasierter Testsysteme und LFTs untersucht. Es konnten funktionsfähige Demonstratoren realisiert und die prinzipielle quantitative Auswertbarkeit der Systeme gezeigt werden. Die Ergebnisse bilden eine belastbare Grundlage für zukünftige multiparametrische, digitalisierte Schnelltestsysteme. Ergänzend wurde ein modular aufgebautes Lehrkonzept mit Bausatz und Erklärvideo entwickelt, das die molekularen Grundlagen immunochromatographischer Schnelltests handlungsorientiert vermittelt und den Transfer der Projektergebnisse in Schule und Hochschule unterstützt.Within the RUBIN innovation cluster SNiPoCC, a subproject was carried out to develop quantitative and digitally readable point-of-care test systems. The objective was the methodological and technological advancement of lateral flow tests (LFTs) and paper-based analytical devices (PADs) for veterinary diagnostics. A Raman-based line-focus readout system with homogenized beam profile and a camera-based photometric detection unit were developed. Automated spectral and image-based data processing algorithms were implemented, including a dedicated software module for nonlinear (quadratic) regression with integrated uncertainty calculation. In addition, the suitability of laser-induced breakdown spectroscopy (LIBS) for elemental analysis of paper-based test systems and LFTs was investigated. Functional demonstrators were realized, and the fundamental feasibility of quantitative evaluation was demonstrated. The results provide a robust foundation for future multiparametric and digitally integrated rapid diagnostic systems. In addition, a modular teaching concept including a hands-on test kit and explanatory video was developed to convey the molecular principles of immunochromatographic rapid tests and to facilitate knowledge transfer to schools and higher education
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