1,720,964 research outputs found
Karyotypic characterization of Acipenser gueldenstaedti with C-, AgNO3, and fluorescence banding techniques
No full textA karyotypic analysis was carried out on the Russian sturgeon using C- and Ag-NOR banding techniques and base specific DNA-binding fluorochromes. The standard karyotype is 2n = 258+/-4. Nucleolar organizer regions are localized on each of the telomers of four metacentric chromosomes, and on one telomer of four metacentric, four acrocentric, and one large metacentric. C-bands are mainly located at the centromeric regions of the acrocentric chromosomes. The biarmed chromosomes exhibit either weak or absent C-bands, but four metacentrics are completely heterochromatic. By means of double staining with complementary fluorochromes, chromomycin A(3) and DAPI, a pattern of fluorescent regions is recognizable. Interspersion of the opposite DNA base pairs along the chromosomes is discussed
Chromosome banding in sturgeons
No full textThe article reviews the present knowledge of chromosome banding in sturgeons and summarizes recent findings obtained by both classical banding techniques (C-banding, fluorescent and silver staining) and molecular methods, such as fluorescent in situ hybridization (FISH). The results are discussed in relation to karyotype organization and chromosome evolution in sturgeons
Cytogenetic characterization of cell lines from three sturgeon species
No full textCell lines were established from three sturgeon species. All were maintained for more than 15 subcultures. The cytogenetic characterizationof the three lines yielded the following results: Acipenser baeri 2n=246+/-10, Huso huso 2n = 120 +/- 8, and Acipenser transmontanus 2n = 246 +/- 10
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
Identification of interspecific hybrids by amplified fragment length polymorphism: the case of sturgeon
No full textThe identification of interspecific hybrids represents an important issue for conservation biology and trade controls. In Italy, the commercial demand for sturgeon is rapidly increasing and interspecific hybrids represent a relevant part of aquacultural production. In this study we tested the suitability of the amplified fragment length polymorphism (AFLP) technique for sturgeon hybrid detection. Multilocus AFLP profiles were analysed by cluster analysis and assignment tests based on observed and simulated samples. Our results show that this approach can easily identify sturgeon hybrids, encouraging its application not only in sturgeon but also in other systematic groups
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
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