1,720,994 research outputs found
Diagnostic advances in viral hepatitis: the discovery of hepatitis C virus and genetic heterogeneity of hepatitis B virus
No full textPREPARATION AND CHARACTERIZATION OF CHITOSAN AND CHITOSAN/HYALURONIC ACID HYDROGELS FOR BIOMEDICAL APPLICATIONS
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Spectroscopical properties of organic/metal nanohybrids
No full textTo prepare stable nanohybrids of controlled size and shape consisting of a noble metal core decorated with polydiacetylenes (PDAs) was the aim of our work. Due to the combination of the outstanding linear and nonlinear optical properties of the polydiacetylenic chains with the electromagnetic field-enhancing capability of metal nanostructures, these novel composites can find potential application in different fields. In particular, the different colours exhibited by PDAs in relation to the monomer chemical nature and the polymerization procedure as well as in response to environmental perturbations make them excellent materials for the fabrication of sensing devices.
On the basis of our previous work on PDA self-assembled monolayers on flat metal surfaces, whose results are briefly reported, we prepared differently-shaped gold and silver nanocores (spheres, cages) coated with various diacetylenic monomers having end-groups able to firmly anchor to the metal surface. These nanohybrids exhibit in aqueous colloidal solution an enhanced photochemical polymerization monitored step by step with UV-Vis and SERS techniques. It is shown that in these stable assemblies an intra-particle polymerization takes place and that the dominant PDA form is conditioned by the core size and geometry. While the nanoparticles are SERS active in the visible, the nanocages are excellent SERS substrates from the visible to the near infrared regions
OPTICAL PROPERTIES OF SELF-ASSEMBLED COLLOIDAL PHOTONIC CRYSTALS DOPED WITH CITRATE-CAPPED GOLD NANOPARTICLES IN "BIOMIMETIC AND SUPRAMOLECULAR SYSTEMS RESEARCH"
No full textData fusion approach for learning transcriptional Bayesian networks
No full textThe complexity of gene expression regulation relies on the synergic nature underlying the molecular interplay among its principal actors, transcription factors (TFs). Exerting a spatiotemporal control on their target genes, they define transcriptional programs across the genome, which are strongly perturbed in a disease context. In order to gain a more comprehensive picture of these complex dynamics, a data fusion approach, aimed at performing the integration of heterogeneous -omics data is fundamental. Bayesian Networks provide a natural framework for integrating different sources of data and knowledge through the priors’ use. In this work, we developed an hybrid structure-learning algorithm with the aim of exploiting TF ChIP-seq and gene expression (GE) data to investigate disease-specific transcriptional regulations in a genome-wide perspective. TF ChIP seq profiles were firstly used for structure learning and then integrated in the model as a prior probability. GE panels were employed to learn the model parameters, trying to find the best heuristic transcriptional network. We applied our approach to a specific pathological case, the chronic myeloid leukemia (CML), a myeloproliferative disorder, whose transcriptional mechanisms have not yet been deeply elucidated. The proposed data-driven method allows to investigate transcriptional signatures, highlighting in the obtained probabilistic network a three-layered hierarchy, as a different TFs influence on gene expression cellular programs
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