1,720,974 research outputs found
The accumulation and metabolism of methylamine organic osmolytes in elasmobranch fishes
No full textIt is widely accepted that marine elasmobranch fishes accumulate the methylamine compounds trimethylamine oxide (TMAO), glycine-betaine (betaine) and sarcosine as osmolytes. The metabolism and accumulation of these compounds has received relatively little study in elasmobranchs, and as such the purpose of this thesis was to investigate aspects of methylamine metabolism, retention and accumulation. Experimental approaches range from multispecies comparisons to directed study of a single species (the winter skate, Leucoraja ocellata ) at different levels of organization from the whole animal down to subcellular components. -- Marine elasmobranchs and a euryhaline species in freshwater accumulate methylamines as the predominant intracellular non-urea organic osmolytes in muscle, whereas, freshwater species preferentially accumulated the β-amino acid taurine. All elasmobranch species examined in this thesis had measurable enzymatic capacity for betaine synthesis in the liver and strong correlation between hepatic betaine synthesizing enzymes and muscle betaine content was found. Only one species of the seven examined had measurable TMAO synthetic capacity and a phylogenetic explanation is proposed for the distribution of TMAO synthesis in elasmobranch fishes. -- In a detailed study of TMAO metabolism in the winter skate, it was concluded that the presence of flavin-containing monoxygenase activity does not indicate the capacity for the synthesis of TMAO. Winter skates lack measurable endogenous TMAO synthesis, apparently obtaining this compound in the diet, and maintain levels without feeding as a result of very low whole animal TMAO losses (<1% day -1 ). Betaine synthesis was also examined in detail in the winter skate, where the liver and kidney are the likely sites of synthesis. The enzymes of betaine synthesis from choline, choline dehydrogenase and betaine aldehyde dehydrogenase, are localized in the mitochondria, as is the case in other animals. Winter skates do not activate betaine synthetic capacity in response to food deprivation or accumulate betaine in the muscle when exposed to a hyperosmotic challenge; however, muscle betaine content increases when they are fed a high betaine diet, suggesting exogenous methylamine supply may be a key determinant in muscle methylamine accumulation in elasmobranchs.Includes bibliographical references
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
The accumulation, synthetic capacity and intertissue distribution of trimethylamine oxide in deep-sea fish and the cold adapted smelt (Osmerus mordax)
No full textTrimethylamine oxide (TMAO) is common to most marine fishes; however, the role TMAO plays in the physiology of marine fish is not well understood. I have used two distinct TMAO accumulating fish 'types', deep-sea fish and smelt (Osmerus mordax), to compare differences in the levels, intertissue distribution and capacity for synthesis of TMAO in fish with high and low levels of TMAO. Several consistencies were found. The intertissue distribution of TMAO showed a trend of locomotory muscle > heart > liverliver ≅ kidney ≅ brain. Levels of trimethylamine oxidase, the enzyme required for TMAO synthesis, did not correlate with higher tissue TMAO content indicating that enhanced endogenous synthetic capacity is not responsible for elevated TMAO content. Finally, evidence for the active uptake of TMAO into striated muscle and the regulation of TMAO concentration in white muscle is presented, possibly due to some role TMAO plays in muscle function.Includes bibliographical reference
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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