1,721,020 research outputs found
The inhibitory effect of difluoromethane on CH4 oxidation in reconstructed peat columns and side-effects on CO2 and N2O emissions at two water levels
No full textMethane emissions from soils are the net result of two processes: methane (CH4) production and CH4 oxidation. In order to understand how both processes respond to environmental changes, it is necessary to distinguish between CH4 production and oxidation. In bacterial cultures and small soil samples, difluoromethane (CH2F2) was found to inhibit CH4 oxidation reversibly, without affecting CH4 production. Hence, CH2F2 allows the study of CH4 production directly and of CH4 oxidation indirectly. To our knowledge, however, the inhibitory effect of CH2F2 within soil columns has not yet been evaluated. We therefore tested which CH2F2 concentration is needed for complete inhibition of CH4 oxidation in reconstructed 28 cm high peat soil columns under different water levels (WL). We found that soil columns require considerably higher headspace CH2F2 concentrations for complete inhibition of CH4 oxidation than small soil samples. Inhibition remained complete until ca. 24 h after CH2F2 exposure. Then, the inhibitory effect diminished. The time needed for the inhibitory effect to disappear depended on WL: at a low WL of -15 cm, the inhibitory effect declined slowly and oxidation rates recovered by 90% only after 12 days. At WL = -5 cm, CH4 oxidation recovered much faster (90% recovery after ca. 3 days). Last, CH2F2 addition significantly decreased the N2O emissions, whereas CO2 emissions remained unaltered. (C) 2009 Elsevier Ltd. 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
Temperature dependence of greenhouse gas emissions from three hydromorphic soils at different groundwater levels
No full textAbstract: Wetlands contribute considerably to the global greenhouse gas (GHG) balance. In these ecosystems, groundwater level (GWL) and temperature, two factors likely to be altered by climate change, exert important control over CO2, CH4 and N2O fluxes. However, little is known about the temperature sensitivity (Q10) of the combined GHG emissions from hydromorphic soils and how this Q10 varies with GWL. We performed a greenhouse experiment in which three different (plant-free) hydromorphic soils from a temperate spruce forest were exposed to two GWLs (an intermediate GWL of 1220 cm and a high GWL of 125 cm). Net CO2, CH4 and N2O fluxes were measured continuously. Here, we discuss how these fluxes responded to synoptic temperature fluctuations. Across all soils and GWLs, CO2 emissions responded similarly to temperature and Q10 was close to 2. The Q10 of the CH4 and N2O fluxes also was similar across soil types. GWL, on the other hand, significantly affected the Q10 of both CH4 and N2O emissions. The Q10 of the net CH4 fluxes increased from about 1 at GWL = 1220 cm to 3 at GWL = 125 cm. For the N2O emissions, Q10 varied around 2 for GWL = 1220 cm and around 4 for GWL = 125 cm. This substantial GWL-effect on the Q10 of CH4 and N2O emissions was, however, hardly reflected in the Q10 of the total GHG emissions (which varied around 2), because the contribution of these gases was relatively small compared to that of CO2
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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