1,721,020 research outputs found
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
Tracing the effects of diets in freshwater fish using fatty acid profiles
Full text linkThe aim of the research included in this dissertation is to contribute to our knowledge of how fatty acids can be used as diet indicators in freshwater systems. More precisely this work was an effort to explore a tool that can be used to describe what salmonids have consumed during the foraging period of the year and relate that to the materials allocated to embryos. As stomach contents of salmonids are often empty due to stress of capture and since any items that are present offer data only on the most recent meal, other methods of gleaning diet information are gaining popularity. Biochemical tracers, such as fatty acids, accumulate in consumers in patterns that reflect diet compositions, thus providing a view of what has been consumed and assimilated into tissues over many months.
Through the use of controlled feeding experiments, this dissertation explores the efficacy of using fatty acid profiles to both describe and quantify the composition of diets of salmonid species. Much of the work conducted exploring fatty acids in reference to a diet have used diets formulated from dry ingredients whereas the experiments described within this dissertation use natural prey to create diets. As such, data described herein offers a unique look at how fatty acids in a piscivore reflect that of their potential prey items in the wild.
In Chapter 1, I illustrate how fatty acid profiles of prey are reflected in lake trout (Salvelinus namaycush) after 14 weeks of feeding. Juvenile lake trout were fed one of three prey species and individuals were sampled at 4, 8 and 14 weeks. Through comparison of consumer fatty acid proportions to those of their diet, it was determined that each diet is assimilated into a consumer in slightly different patterns. Such a finding is important as it suggests that one cannot simply compare fatty acids in a predator to those of prey without accounting for diet-specific patterns of assimilation.
In Chapter 2, data from the feeding experiment described in Chapter 1 plus two others were used to explore a model that can predict the composition of prey items that have been consumed. Quantitative fatty acid signature analysis (QFASA) involves mathematically combining fatty acid profiles of prey items to yield a profile as similar to a consumer’s as possible. During this modeling exercise, I found that the most accurate data would be gained if data for each predator-prey relationship was modelled through controlled feeding experiments. This exercise was conducted with three different consumer species to ensure our results were not species specific.
As a follow-up to Chapter 2, prey fish collected from two different systems were used to test how variability within a prey species affects the ability to estimate a consumer’s diet composition in Chapter 3. Data from this experiment illustrates that trophic indicators established in one freshwater system are applicable to other freshwater food webs. Data also indicated that variability among the species at a trophic level decreases as the trophic level increases. This would suggest that at higher trophic levels it might not be possible to differentiate between similar prey species consumed.
As previous experiments herein used simplistic diets composed of a single species at a time, Chapter 4 explores the efficacy of fatty acid mixing models when diets consisted of combinations of prey items. Specifically, a feeding experiment was conducted that included diets of one of three invertebrate species along with even mixtures of each pair of invertebrates and a mixture of all three. Using lake trout fed the mixed diets as pseudo-wild or individuals with unknown diets, we compared their fatty acid profiles to those of the individuals fed monotypic diets. Data from this experiment indicated that diets of mixed compositions may predictably alter fatty acid profiles of consumers but quantitative models may not be as accurate as previously assumed.
As a final study, in Chapter 5, adult brown trout (Salmo trutta) were used to investigate how diets of nonnative fish species from the Great Lakes may affect the fatty acids allocated to embryos. Data described within this chapter indicate that the fatty acid profiles of salmonid eggs are drastically altered by the composition of the diet. Such a result indicates that maternal diets may act as a parental care mechanism, and that genetic strains of salmonids that disfavor or are behaviorally unlikely to consume certain items may help alleviate the demand on stocking programs.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2019-08-01The student, Austin Happel, accepted the attached license on 2017-06-19 at 09:45.The student, Austin Happel, submitted this Dissertation for approval on 2017-06-19 at 09:53.This Dissertation was approved for publication on 2017-06-23 at 15:27.DSpace SAF Submission Ingestion Package generated from Vireo submission #11236 on 2017-09-29 at 10:45:57Made available in DSpace on 2017-09-29T17:45:13Z (GMT). No. of bitstreams: 3
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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
Newsletter Spring 2018: Environmental Science & Ecology
Full text linkNewsletter from the Department of Environmental Science and Ecology for Spring 2018. This newsletter highlights the phased retirement of Dr. Doug Wilcox, says goodbye to Visiting Assistant Professor Dr. Nathan Kleist, and shares the research activities of faculty and students, and updates from several alumni.https://digitalcommons.brockport.edu/env_news/1019/thumbnail.jp
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Full text linkNewsletter Fall 2017: Environmental Science & Ecology
No full textNewsletter from the Department of Environmental Science and Ecology for Fall 2017. This newsletter highlights the sabbatical of Dr. Chris Norment, welcomes two new Assistant Professors, Dr. Courtney McDaniel and Dr. Michael Chislock and Visiting Assistant Professor Dr. Nathan Kleist. It shares the research activities of faculty and students, and updates from several alumni.Archived web contentSUNY BrockportEnvironmental Science & Ecology Department Newsletter
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
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