1,720,957 research outputs found
Effect of polIII dependent elements on CAT reporter gene transcription in Nicotiana tabacum protoplasts
No full textThe expression of LESK1 morphogenetic marker along the tomato hypocotyl axis is linked to a position-dependent competence for shoot regeneration
No full textSomatic morphogenesis is an important process whose mechanisms are still not completely understood. This is partially due to the lack of reliable morphogenetic markers that identify the different stages of the process. In the present work, a fragment of LESK1 gene (Lycopersicon esculentum shoot kinase 1) has been utilized as a marker of somatic caulogenesis. The expression of this marker pointed out a particular abundance of the corresponding transcript in tomato hypocotyls from 8-day-old plantlets. This elevated expression underlines the particular attitude to regeneration of this organ. Hypocotyl explants can in fact regenerate in the absence of exogenous growth regulators giving rise to shoot and root production at the apical and basal ends, respectively. The polarization observed in morphogenesis is always associated with polarized expression of LESKI gene, which is elevated at the top of the explants. where shoot production occurs, and low at the basal pole, where roots were observed. A non-homogeneous LESKI expression was also found along the hypocotyl axis where apparently marks cell populations with different competence to caulogenesis. These different levels of competence may be due to a variation in cell sensitivity to growth regulators, or the reaching of a well determined hormonal ratio required by the cells to be driven toward caulogenesis. LESK1 represents a reliable marker probably linked to the acquisition of competence for somatic caulogenesis
STUDI DI BIODEGRADABILITÀ DELL’1,2-DICLOROETANO IN IMPIANTI DI DEPURAZIONE A FANGHI ATTIVI E FILTRI PERCOLATORI IN SCALA RIDOTTA. ARRICCHIMENTO E CARATTERIZZAZIONE DELLA COMUNITÀ BATTERICA
No full text“Characterization of a bacterial community enriched from a laboratory scale system for treatment of groundwaters contaminated by 1,2-dichloroethane”.
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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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