1,720,956 research outputs found
Quellen und Vorkommen kurzkettiger Alkylphenole (SCAP)
No full textAus der Literaturrecherche und eigenen Untersuchungen geht hervor, dass kurzkettige Alkylphenole (SCAP) während der Verarbeitungs- bzw. Veredelungsprozesse fester fossiler Brennstoffe ebenso in die Umwelt freigesetzt werden können, wie basierend auf Prozessen verschiedenster Industrien. Die große Bandbreite an Verwendungs- und Anwendungsmöglichkeiten von SCAP bringt viele Eintragsmöglichkeiten in die Umweltmedien mit sich. Prägnant sind die prozessbedingten SCAP-Muster (vorkommende Einzelsubstanzen) der verschiedenen Industrien und Produkte, wodurch Eintragsquellen und Fließpfade genauer quantifiziert werden können. Natürliche Eintragsquellen von SCAP mit Konzentrationen bis zu mehreren Tausend ppm sind ausschließlich Erdöle bzw. erdölführende Gesteine. Dieser Sachverhalt in Verbindung mit ihren chemisch-physikalischen Eigenschaften begründet die Verwendung der SCAP als Fluss- und Prozessindikatoren in der Erdöl-Reservoir-Erkundung und -Förderung. Anlehnend daran ist der oft noch fehlende Kenntnisstand der Umweltrelevanz und -akzeptanz von SCAP in Grundwasser-Schadensfällen in Deutschland nicht nachzuvollziehen. Es wird verdeutlicht, dass SCAP neben Erdölreservoiren auch für den Wasserkreislauf als Fluss- und Prozessindikatoren prädestiniert sind
A case study on the correlation of micro-contaminants and potassium in the Leine River (Germany)
No full textRiver monitoring with focus on the correlation of 41 micro-contaminants with K(+) and its temporal and spatial variation was carried out in the Leine River (Germany). A positive correlation of concentrations of wastewater-related micro-contaminants and K(+) is to be expected in receiving waters of wastewater treatment plant (WWTP) effluent since urine is a significant source of K(+) in WWTP effluent. This correlation was found for compounds, which meet the following criteria: (1) WWTP effluent is the dominating source of the compound, (2) variability of its mass flux in the WWTP is negligible, and (3) the compound is persistent in WWTPs and in the environment. The excellent positive correlation of carbamazepine with K(+) resulted in the fitting of a universal linear equation to the summer and winter data. For almost all other correlating compounds (1H-benzotriazole, citalopram, diclofenac, metoprolol, sotalol, sulfamethoxazole and tolyltriazole), slopes of the line fittings were steeper in winter (x-axis: K(+), y-axis: respective micro-contaminant). This has been attributed to a presumed lower degree of degradation and attenuation within WWTPs and in the environment due to low temperatures as well as an increase in consumption of these compounds in the winter months. As part of this research, a sampling event along the entire flow path of the Leine River (similar to 280 km) was conducted to identify compounds demonstrating stable ratios of various respective micro-contaminants with K(+). Among other compounds, carbamazepine, sulfamethoxazole, and tolyltriazole demonstrated the best correlations with R(2) > 0.89. Potassium-equivalents of the individual micro-contaminants depended on land use and population structure of the investigated river section. (C) 2011 Elsevier Ltd. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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