1,720,980 research outputs found
Dissolved organic matter composition in Antarctic streams (Sôya Coast, Lützow-Holm Bay, East Dronning Maud Land, East Antarctica) derived from FT-ICR-MS analyses during JARE58
No full textThe sampling campaign was conducted during the austral summer in January 2017 as a part of the 58th Japanese Antarctic Research Expedition. There are several ice-free areas on Sôya Coast with hundreds of lakes and several streams, which were formed during the last 7,000 years under the glacier retreat and iso-static uplifts that occurred after the Last Glacial Maximum. The Langhovde ice-free area is located ~25 km away from Japan's Syowa Station. The Yukidori and Yatsude Valleys in Langhovde run from the edge of the continental ice sheet to Lutzow-Holm Bay. At each stream of the valleys, water samples were directly collected into 550-mL volume polyethylene terephthalate bottles after rinsing more than three times with the collected water. The collected waters were filtered in a field laboratory within a few hours after sampling. Samples were filtered through pre-combusted (450dc, >3 h) glass-fiber filters (nominal pore size 0.3mm, GF-75, Advantec, Tokyo, Japan) into pre-combusted glass bottles (see doi:10.1016/J.WATRES.2019.114901). The filtered samples were immediately spiked with sodium azide (final concentration of 0.02%) for preservation, stored dark at 5dc, and shipped back to Japan. DOM was extracted and desalted prior to FT-ICR MS analysis following an established method using cartridges filled with a styrene-divinylbenzene copolymer (Agilent Bond Elut PPL, 100 mg). Depending on the DOC concentration, the volume used for extraction was adjusted such that 4 µmol C was applied to each cartridge. We performed a mass spectrometric analysis of DOM extracts via FT-ICR MS on a 15 Tesla solariX XR Fourier-transform ion cyclotron resonance mass spectrometer (Bruker Daltonik GmbH, Bremen, Germany). The system was equipped with an electrospray ionization source (ESI, Bruker Apollo II) applied in negative ionization mode. Methanol extracts were mixed with ultrapure water (50:50 v/v) for FT-ICR MS analysis and diluted to a final DOC concentration of 2.5 mg C/L. 200 single scans with an ion accumulation time of 0.1 s were recorded over a mass range of m/z 92 to 2,000 Da and added to one spectrum. Data processing, molecular formulae assignments, and compound category classifications were done with the software package ICBM-OCEAN
Molecular formulae assignments and compound category classifications from the 58th Japanese Antarctic Research Expedition
No full textThe sampling campaign was conducted during the austral summer between December 2016 and February 2017 as a part of the 58th Japanese Antarctic Research Expedition. On Sôya Coast (Lützow-Holm Bay, East Dronning Maud Land, East Antarctica), there are hundreds of lakes with variable water chemistry which were formed during the last 7,000 years under the glacier retreat and iso-static uplifts that occurred after the Last Glacial Maximum. Water samples were collected either at the center of the lakes or at the shore into 550-mL PET bottles after rinsing more than three times with the collected water. Within a few hours after sampling, samples were filtered through pre-combusted (450dc, >3 h) glass-fiber filters (nominal pore size 0.3mm, GF-75, Advantec, Tokyo, Japan) into pre-combusted glass bottles (see doi:10.1016/J.WATRES.2019.114901). The filtered samples were immediately spiked with sodium azide (final concentration of 0.02%) for preservation, stored dark at 5dc, and shipped back to Japan. DOM was extracted and desalted prior to FT-ICR MS analysis following an established method using cartridges filled with a styrene-divinylbenzene copolymer (Agilent Bond Elut PPL, 100 mg). Depending on the DOC concentration, the volume used for extraction was adjusted such that 4 µmol C was applied to each cartridge. We performed a mass spectrometric analysis of DOM extracts via FT-ICR MS on a 15 Tesla solariX XR Fourier-transform ion cyclotron resonance mass spectrometer (Bruker Daltonik GmbH, Bremen, Germany). The system was equipped with an electrospray ionization source (ESI, Bruker Apollo II) applied in negative ionization mode. Methanol extracts were mixed with ultrapure water (50:50 v/v) for FT-ICR MS analysis and diluted to a final DOC concentration of 2.5 mg C/L. 200 single scans with an ion accumulation time of 0.1 s were recorded over a mass range of m/z 92 to 2,000 Da and added to one spectrum. Data processing, molecular formulae assignments, and compound category classifications were done with the software package ICBM-OCEAN
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
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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