1,721,009 research outputs found
Nanoparticles effects on growth and differentiation in cell culture of Daucus carota
No full textNanoparticles (NPs) effects on developmental processes like cell
growth, de-differentiation, and embryogenesis were analyzed using the in vitro model
system of Daucus carota L. somatic embryogenesis. Fe3O4 NPs, 6 nm diameter, were
dispensed at doses ranging from 2.01 to 33.5 mg/l to carrot in vitro cultures at different
times, along the stages of cell growth and embryogenic differentiation. Moreover, the
mitotic index of cell cultures under treatments has been cytologically determined. The
results demonstrated that Fe3O4 NPs exposure from 2.01 to 6.70 mg/l slightly affected
growth, mitotic index, and de-differentiation. At the dose of 20.10 mg/l cell growth
and relative mitotic index dropped dramatically, and stopped completely at 33.5 mg/l.
Moreover, these higher doses, entirely blocked embryo formation when treatments were
done along somatic embryogenesis induction. Therefore, this model system seems well
suited to check NPs impact on developmental processes
Indagini in acqua
No full textSi riportano le strutture archeologiche rinvenute nel fiume Tevere con le prospezioni multibea
Indagini geofisiche per lo studio dei terreni e delle fondazioni di strutture archeologiche.
No full textSi utilizzano tecniche geofisiche per la ricostruzione dell'assetto geologico del Palatin
Field Experiment for Characterization of GPR Antenna and Pulse Propagation
No full textProductive interpretations of ground penetrating radar surveys require an accurate understanding of electromagnetic wave
radiation, propagation, and scattering in geological materials as well as accurate knowledge of the reflection characteristics of
various target anomalies embedded in such materials. GPR responses and survey profiles are often interpreted on the basis of
theoretical estimates and numerical simulation models of electromagnetic wave propagation in simplified representations of
ground materials and by using idealized target contrasts and geometries. Alternatively, field experiments performed under
controlled test conditions can also be effective in demostrating GPR system performance capabilities and in providing quantitative
measurements in realistic geologic formations. Experimental research at the University of Rome "La Sapienza" and at the
Italian National Research Council were initiated to develop a basic understanding of the radiation and scattering characteristics
of VHF pulse-mode GPR signals in earth materials and in air with emphasis on antenna ground coupling and target backscatter
responses. The results of the experimental measurements conducted in air provided baseline information on the GPR system and
target reflections under lossless propagation conditions. Target response measurements at various burial depths provided a
systematic data base from which target responses, propagation parameters of the medium, and relevant data processing techniques
were evaluated to gain useful insights into their interpretations.
Other more advanced experimental tests are planned for the future
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
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