1,720,992 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
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
Anomericity of T‑2 Toxin-glucoside: Masked Mycotoxin in Cereal Crops
No full textT-2
toxin is a trichothecene mycotoxin produced when Fusarium fungi infect grains, especially oats and
wheat. Ingestion of T-2 toxin contaminated grain can cause diarrhea,
hemorrhaging, and feed refusal in livestock. Cereal crops infected
with mycotoxin-producing fungi form toxin glycosides, sometimes called
masked mycotoxins, which are a potential food safety concern because
they are not detectable by standard approaches and may be converted
back to the parent toxin during digestion or food processing. The
work reported here addresses four aspects of T-2 toxin-glucosides:
phytotoxicity, stability after ingestion, antibody detection, and
the anomericity of the naturally occurring T-2 toxin-glucoside found
in cereal plants. T-2 toxin-β-glucoside was chemically synthesized
and compared to T-2 toxin-α-glucoside prepared with Blastobotrys muscicola cultures and the T-2 toxin-glucoside
found in naturally contaminated oats and wheat. The anomeric forms
were separated chromatographically and differ in both NMR and mass
spectrometry. Both anomers were significantly degraded to T-2 toxin
and HT-2 toxin under conditions that mimic human digestion, but with
different kinetics and metabolic end products. The naturally occurring
T-2 toxin-glucoside from plants was found to be identical to T-2 toxin-α-glucoside
prepared with <i>B. muscicola</i>. An antibody test for
the detection of T-2 toxin was not effective for the detection of
T-2 toxin-α-glucoside. This anomer was produced in sufficient
quantity to assess its animal toxicity
Cytology, cell walls and septa:A summary of yeast cell biology from a phylogenetic perspective
No full textThis chapter aims to present an overview of yeast cell biology, biochemical structure and composition of cell walls in various yeast species, septal pore ultrastructure, and other subcellular characteristics, and a phylogenetic framework to these observations. Yeast cells have ultrastructural features typical of other eukaryotic cells, which include the presence of membrane-bound organelles. Through the use of microscopic techniques, yeast cells have been the topic of detailed structural research for many decades. Because of their relatively small size, electron microscopy is an essential tool for the study of the cellular ultrastructure of the cell. Yeast cells contain all subcellular structures typical of eukaryotes. These structures include the cytoskeleton, a nucleus and various subcellular organelles such as the endoplasmic reticulum (ER), the Golgi apparatus, mitochondria, and microbodies. Like plants, yeast cells contain a vacuole, and the plasma membrane is surrounded by a rigid cell wall. However, chloroplasts are absent in all fungi, which include the yeasts. Fluorescence microscopy methods have become an attractive tool for studying living yeast cells due to the availability of novel fluorescent dyes and the introduction of genes that encode fluorescent proteins. Upon introduction of hybrid genes encoding a fluorescent protein fused to a yeast protein, any subcellular structure can be specifically marked and its kinetics analyzed in real time in living yeast cells.</p
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