1,721,143 research outputs found
Impact of soil organic matter heterogeneity and soil aggregation on the sorption of herbicides by soils
No full textExperiments were performed in pursuit of understanding of interactions between herbicides and soils, focusing on the effects of heterogeneity within soil organic matter (SOM), and the aggregation of SOM with mineral matter in soils, on equilibrium sorption and sorption rates of herbicides. For this purpose, sorption of three herbicides -- atrazine, metolachlor and napropamide -- was studied on a bulk soil, a bulk peat and three fractions that were chemically isolated from it. Studies were also performed using the well studied polynuclear aromatic hydrocarbon (PAH) phenanthrene to provide a comparison for the herbicides. The sorbents extracted from the soil and peat -- Base extracted fraction (BE), humic acids fraction (HA) and kerogen and black carbon fraction (KB) were characterized with elemental analysis, scanning electron microscopy and surface area measurements and subjected to sorption and desorption equilibrium studies and sorption rate investigations.
The herbicides were found to exhibit non linear sorption isotherms on all the sorbents, with HA from both soil and peat showing the least non linear isotherms and fastest sorption rates among all the sorbents. HA fraction also showed the least dependence of equilibrium or time dependent organic carbon normalized sorption capacity (KOC or KOC(t)) on initial aqueous solute concentration. This result was in accordance with the amorphous nature of the HA material and similar to that observed for PAHs. Herbicide atrazine was found to react with HA and was transformed to hydroxyatrazine in its presence. KOC or KOC(t) values for all other sorbents were found to be dependent on initial aqueous solute concentration. High sorption capacity of KB dominated the sorption for all the herbicides, with this capacity being diminished by the aggregation structure of the soil. Significant sorption hysteresis was not observed for the sorption of herbicides on the KB fraction, unlike that observed for phenanthrene, indicating large herbicide molecules do not penetrate nanopores of KB. Hysteresis observed for the bulk soil and BE for atrazine was attributed to chemical interactions between the sorbents and the herbicide. Overall this dissertation found that the herbicides exhibit hydrophobic interactions with soils, similar to PAHs, but owing to their large molecular sizes and polarities may exhibit site specific interactions and lack of hysteresis with soil components that call for changes in existing fate and transport models and further microscopic understanding.Ph.D.Includes bibliographical references (p. 158-169)
Manu Samriti Chander\u27s Brown Romantics: Poetry and Nationalism in the Global Nineteenth Century
No full textThe last decade has witnessed increasing critical interest in questions of race, nation, and empire during the Romantic era. Manu Samriti Chander\u27s Brown Romantics: Poetry and Nationalism in the Global Nineteenth Century contributes to this discussion by examining the extensive international impact of Romantic poetry on writers beyond Britain. Part of Bucknell University Press\u27s Transits: Literature, Thought, and Culture series, his work provides a fascinating and unique perspective on global literary relations. He demonstrates how Henry Derozio of India, Egbert Martin of British Guiana, and Henry Lawson of Australia adopted the role of the Romantic author to shape nationalist movements in their countries and mediate their colonial relationship with England. By reading British writers in relation to those of other nations, Brown Romantics questions the privileging of a Eurocentric canon and challenges us to widen our definition of ‘Romantic’ literature
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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