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Contribution to the knowledge of lichen flora of inland sand dunes in the western Po Plain (N Italy)
No full textThis paper describes the lichen flora surveyed in inland sand dunes, called dossi, in the western Po Plain (Lombardy region, Italy). Here, lichens were marginally known in comparison with the epigaeous component, but they were never studied before in relation to the epiphytic, epixylic and epilithic components. The floristic list includes 50 species; ecological and chorological analyses were carried out. Thirteen lichen species observed on various substrata were not reported in the lichen list of the Ticino Natural Park, which distances only few kilometres from our study area. Nine species are new for the Po phytoclimatic region and one species, Cladonia portentosa, is new for Lombardy. Particularly interesting are some species related to the Corynephorus grasslands, such as Cladonia sp. pl. and Stereocauloncondensatum, and three species usually absent, at our latitudes, beneath the montane belt: Cladonia digitata, Hypocenomyce scalaris and Parmeliopsis ambigua. These data confirm the importance of inland sand dunes for lichen diversity of the Po Plain. Some preliminary remarks concerning the management of the habitats hosting lichens are given, with particular emphasis to their conservation. Suggested actions include the possibility to keep woody coarse debris, to favour epixylic species, and mechanical disturbance, dispersal of lichen fragments and sheep grazing, to favour epigaeous species
Binding of distamycin and chromomycin to human immunodeficiency type 1 virus DNA: a non-radioactive automated footprinting study
No full textSequence-selectivity of DNA-binding drugs was recently reported in a number of studies employing footprinting and gel retardation approaches. In this paper we studied sequence-selectivity of the binding of chromomycin and distamycin to DNA by performing DNase I footprinting and analysis of the cleaved fragments by the Pharmacia ALF DNA Sequencing System. As a model system we employed the long terminal repeat of the human immunodeficiency type 1 virus. The main conclusion of our experiments is that automated analysis of DNase I footprinting is a fast and reliable technique to study drugs-DNA interactions. The results obtained suggest that distamycin and chromomycin differentially interact with the long terminal repeat of the human immunodeficiency type 1 virus; this differential binding depends upon the DNA sequences recognized. The data presented are consistent with a preferential binding of distamycin to DNA sequences of the binding sites of nuclear factor kappa B and transcription factor IID. By contrast, distamycin exhibits only weak binding to DNA sequences recognized by the promoter-specific transcription factor Sp1. Unlike distamycin, chromomycin preferentially interacts with the binding sites of the promoter-specific transcription factor Sp1
Contribution to the knowledge of lichen flora of inland sand dunes in the western Po Plain (N Italy)
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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
Differential effects of distamycin analogues on amplification of human gene sequences by polymerase-chain reaction
No full textIn this report we analyse the effects of distamycin and five distamycin analogues on amplification by polymerase-chain reaction (PCR) of two gene sequences displaying a different A+T/G+C content. The first was a 5' region of the human oestrogen receptor (ER) gene, containing a (TA)26 stretch; the second was a CG-rich sequence of the human Ha-ras oncogene. The results obtained unequivocally demonstrate that the addition of one pyrrole ring significantly improves the ability of distamycin derivatives to interfere with PCR-mediated amplification of the human ER genomic region carrying a (TA)26 stretch. The distamycin analogues analysed differ in the number of pyrrole rings and in the presence of an N-formyl, an N-formimidoyl or a retroamide group at position X1. Among compounds carrying the same number of pyrrole rings, those carrying an N-formyl or an N-formimidoyl group retain a similar inhibitory activity. The retroamide analogues, on the contrary, are much less efficient in inhibiting PCR-mediated amplification of the 5'ER region. With respect to sequence selectivity both distamycin and distamycin analogues exhibit a sequence preference, since they do not inhibit PCR amplification of Ha-ras CG-rich gene regions, with the exception of a distamycin analogue carrying four pyrrole rings
Distamycin-treated MCF7 cells: inhibition of PCR-mediated amplification of a TA-rich region of human estrogen receptor gene
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