1,720,998 research outputs found
Genome size variation in tardigrada
No full textIn this paper the genome size evaluation is extended to 8 species of eutardigrades and one species of eterotardigardes in order to obtain a more comphrensive picture of minimun DNA content evolution in the phylum Tardigrada.Genome size and sperm cell morphology are correlated. In the phylum low genome size could be correlated to the high specialization of the phylum
Study an egg today to make an embryo tomorrow
No full textThe sequence of papers starts with an interview of David Albertini and his extraordinary contribution to the knowledge of 'the most wondrous of cells - the oocyte' and follows with a road map of the life of an oocyte from its origin as a primordial germ cell (PGC) to completion of maturation, evidencing the hurdles encountered during this troubled journey. The female gamete is followed during its migration as a PGC towards the gonadal ridge (Mamsen et al.) and during its entry into meiosis (Spiller et al.), when, for the first time, we are able to read a whole genome transcriptional portrait of precious human PGCs in a comparative analysis with that of the mouse (Diedrichs et al.). Then, its growing phase in the adult ovary is described all through to the antral compartment, with a specific focus on metabolic changes (Collado-Fernandez et al.), the role of the Akt signalling pathway (Cecconi et al.) and the developmental relationship occurring between the oocyte and its companion theca, granulosa and cumulus cells within the antral follicle (Hennet and Combelles). During these stages of maturation, the oocyte acquires the zona pellucida, a glycoprotein layer crucial at the time of fertilisation, but, we learn here, also important for the growth of a healthy oocyte (Wassarman and Litscher). The long perdurance of the oocyte within the human ovary, maternal age, hormonal stimulation, disturbed metabolism, and depletion of the follicle pool contribute to mitochondrial dysfunction, spindle aberrations, and errors in chromosome segregation (Eichenlaub-Ritter)
Six-year-old archival chromosome preparations are still good biological reagents for repeated primed in situ labelling (rPRINS).
No full textRiflessioni islandesi
No full textAnalisi bioetica del caso di screening genetico di massa sulla popolazione islandese (2015)
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
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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