1,721,258 research outputs found
Assessment of regeneration and transformation in sweet cherry cultivars
Full text linkThe sheer size of the tree is still one of the most relevant cherry-growing related problems. Genetic transformation with phytochrome genes could contribute to the reduction of tree size in cherry. The responses to morphogenesis and genetic transformation were compared in two sweet cherry commercial cultivars and the characterised somaclone HS. Axenic shoot cultures of ‘Hedelfinger’, ‘Lapins’ and somaclone HS were grown on BA (6-benzylaminopurine) containing medium. The apical portion of each shoot was cultured in the presence of BA and NAA (naphthalene acetic acid) in the dark. After two weeks the callus formed at the base of each shoot, a 3-4 mm upper stem portion deprived of axillary shoots/buds and intact leaves were subcultured on regeneration medium, in the light. A. tumefaciens (C58C1 pGV3850), carrying the p35SGUSIntron binary vector was used to infect shoots deprived of unfolded leaves and lateral buds by either full immersion or basal dipping in the bacterium suspension. After 21 days under light, all tested explants, except ‘Lapins’ stems, showed regeneration ability. All reached their maximum regenerative expression within 56 days and ‘Lapins’ basal callus scored the highest regeneration percentage (50.1%). Basal dipping was chosen as the optimal system to infect the two cultivars and the somaclone which showed a different attitude to produce morphogenic callus. The morphogenic masses kept growing on 50 mg L-1 kanamicine for 40 weeks and the first shoots started to elongate when the BA was reduced by one-fourth. GUS activity was found in the shoot basal cuts and surrounding tissues and this evidence let us deduce that hypothetically transformed cells had chances to take part in either direct or indirect morphogenesis
Circulating knowledge through letters: circulating letters through technologiy: the Eastways of Science project
No full textCorrespondences are one of the most important sources for a science historian: they shed light upon the origins of new scientific theories; they are a privileged point of view to understand the debates of an age of censorship; last but not least correspondences are necessary instruments to understand that extraordinary phenomenon that was the ideal super-national academy of the 17th century European “scientists”. These are some of the reasons why the letter exchanges kept by the «heroes» of modern science still offer material for monumental edition plans. Anyway, if we consider the scientific correspondences as the main source for mapping boundaries, extension, density, population and roadways of the actual “Republic of sciences”, the editions on paper –even if philologically peerless– are widely insufficient to manage the huge mass of information inferred from letters. Eastways of Science is one of the many projects that nowadays exploit the web-technologies to edit, manage and study such documents. It is a research project co-financed by the European Commission, hosted by the University of Rome La Sapienza and technologically implemented by the Rinascimento Digitale Foundation-Institute and the Museum for the History of Science of Florence. It aims at creating an electronic database that would work as a common repository of letters of scientific-historical interest; a register of the men, women, lecturers, practitioners, patrons, institutions, things etc. involved in such a “Republic” (especially as to Middle-East Europe) in the second half of the 17th Century; a «dynamic» database able to reconstruct the networks of scientific relations that crossed early modern Europe –that is the scientific information flows– making them visible on a geographic map. It focuses on the Academy of the Cimento correspondence, and on its intersections with the epistolaries by Johannes Hevelius and Giovanni Alfonso Borelli. This paper aims at explaining and discussing methodologies, ends and temporary results of the project
Il controllo vascolare cavale, delle vene sovraepatiche e delle vene epatiche accessorie.
No full textIl controllo vascolare cavale, delle vene sovraepatiche e delle vene epatiche accessorie.
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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
Istituzioni e vita culturale in età napoleonica
No full textA collective survey on cultural institutions and trends in the Italian Republic and in the Italian Kingdom during the Napoleonic period (1802-1814)
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