1,720,956 research outputs found
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
Causes and Impacts of Thiamine Deficiency Complex in Lake Ontario Salmonines
No full textFor at least 50 years, salmonine species in the Great Lakes region have been suffering from a vitamin deficiency termed Thiamine Deficiency Complex (TDC) (Marcquenski and Brown 1997; Ketola et al. 1999). TDC impacts salmonines at alevin and adult stages, although the most common impacts are observed before first-feeding (Honeyfield et al. 1998; Fitzsimons et al. 1999; Lee et al. 2009). Alevins with TDC experience various neurological problems including lethargy, hyperexcitability, spiraled swimming, and ultimately death (Fitzsimons 1995). However, alevins that do not die directly from TDC may die from secondary effects that limit their feeding and predator avoidance (Fitzsimons et al. 2009; Ivan et al. 2018). Therefore, TDC can reduce offspring survival drastically, limiting wild recruitment and survival in hatcheries. However, thiamine treatments under hatchery conditions have been able to reduce TDC, increasing offspring survival significantly (Fitzsimons 1995; Koski et al. 1999; Fitzsimons et al. 2001; Lee et al. 2009; Futia et al. 2017). Adult salmonines can also experience symptoms of TDC when deficiencies are severe (Brown et al. 2005). Common symptoms include wiggling behavior while swimming, lethargy, and occasionally mortality (Brown et al. 2005; Futia et al. 2017).
Thiamine deficiency in salmonines is not limited to the Great Lakes. In New York’s Finger Lakes, Lake Champlain, and the Baltic Sea, various salmonine species suffer from thiamine deficiency (Fisher et al. 1995; Bengtsson et al. 1999; J. Rinchard, The College at Brockport, Brockport, New York, personal communication, 2018). Despite thiamine deficiency being an international issue that has been occurring for decades, the specific cause has yet to be determined. However, two hypotheses have been proposed: 1) degradation of thiamine by the thiamine-degrading enzyme, thiaminase (Honeyfield et al. 2002; Tillitt et al. 2005), and 2) increased use of thiamine as an antioxidant in response to high dietary lipid content (Lukienko et al. 2000; Keinänen et al. 2012). While both of these hypotheses are plausible, neither has been proven to cause thiamine deficiencies in wild populations.
In the Great Lakes region, alewife (Alosa pseudoharengus) are associated with the occurrence of TDC. Honeyfield et al. (2005) demonstrated that feeding exclusively on alewife induced TDC in adult salmonines. Furthermore, following the collapse of the alewife population in Lake Huron, wild recruitment of lake trout (Salvelinus namaycush) increased (Fitzsimons et al. 2010; Riley et al. 2011). Alewife have elevated thiaminase activity (Tillitt et al. 2005); however, the source of the thiaminase is unknown (Richter et al. 2012). Alewife also have greater lipid content than other abundant offshore prey fish in the Great Lakes (Happel et al. 2017); however, relationships between lipid content of prey and the occurrence of TDC in salmonines has not been proven.
In my thesis study, the extent of TDC for five salmonine species (brown trout Salmo trutta, Chinook salmon Oncorhynchus tshawytscha, coho salmon O. kisutch, lake trout, and steelhead trout O. mykiss) in Lake Ontario was determined from 2015 to 2017. The severity of TDC was determined based on thiamine concentrations in egg, liver, and muscle tissue as well as the occurrence of TDC-induced offspring mortality. Additionally, dietary influence on thiamine concentrations was evaluated. Using fatty acid signature analysis, the inclusion of alewife, rainbow smelt (Osmerus mordax), and round goby (Neogobius melanostomus) in salmonine diets was determined. Lipid content of whole-body prey fish and various tissues of predator species were determined to investigate the influence of fat content on thiamine concentrations. Lastly, the potential effect of lipid peroxidation on salmonine thiamine concentrations was determined by comparing the proportions of fatty acids, grouped based on degrees of unsaturation (i.e., saturated, monounsaturated, and polyunsaturated), in egg and belly flap tissue with thiamine concentrations
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
Fatty Acid Signatures of Lake Michigan Prey
No full textStudying the spatio-temporal variation in fatty acid signatures can increase our understanding of the nearshore food web structure as it continues to shift due to anthropogenic factors. The purpose of this experiment was to compare fatty acid signatures (FAS) of four fish species (alewife, round goby, spottail shiner, and yellow perch) from Lake Michigan. Fish were collected (n=300) along the southwestern shore of Lake Michigan during spring, summer, and fall of 2013 at three sampling sites with different habitat complexity. Their substrates were characterized as sand (site A), rocky (site B), and coarse sand with intermittent cobble and random boulders (site C). Fish were analyzed and FAS were determined based on the quantities of 29 different fatty acids. Significant differences in FAS among fish species were detected (ANOSIM, overall R = 0.796), with alewife and round goby presenting the most distinct FAS (25.5% dissimilarity). The fatty acids responsible for the most variation among species included 16:1n-7, 18:1n-9, 20:5n-3, and 22:6n-3. Spatial and temporal variations in FAS were observed within species. Fatty acid signatures of round goby collected at site B in spring and summer differed significantly (overall R 0.693 and 18.8% dissimilarity), which implies seasonal dietary shifts. Spatial differences in yellow perch FAS were also observed, indicating habitat driven plasticity in yellow perch diets. Although within species spatio-temporal FAS variations were observed, among species FAS differences were consistently larger. These data can be compared to samples from other years to determine annual changes as well. In addition, they can be compared with FAS of predatory fish to determine the diets of those species.SUNY BrockportSUNY Undergraduate Research Conferenc
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
