1,721,239 research outputs found
Response of an integrated system, for the study of complex phenomena monitored by gas radon
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Prostaglandin production by human polymorphnuclear leucocytes during phagocytosis in vitro
No full textConfronto XRF – LIBS per la caratterizzazione chimico-fisiche dei materiali lapidei provenienti dal teatro greco-romano di Taormina
No full textVengono messe a confronto due tecniche spettroscopiche, la fluorescenza a raggi X (XRF) e la ablazione indotta da laser pulsato (LIBS), al fine di caratterizzare la composizione chimico-fisica di
materiali lapidei naturali e non provenienti dal teatro Greco-Romano di Taormina. Entrambe le tecniche permettono un’analisi integrata, offrendo la LIBS la possibilità di ottenere informazioni stratigrafiche.
Verranno presentati i risultati di analisi XRF e LIBS effettuate in situ e in laboratorio sui campioni prelevati nel teatro. L’interpretazione quantitativa delle analisi LIBS è stata effettuata mediante una tecnica standarless, ossia che non richiede l’uso di standard e denominata tecnica Calibration Free (LIBS-CF). Tale tecnica è stata sviluppata presso i laboratori di spettroscopia laser dell’Istituto per i processi Chimico-Fisici del CNR di Pisa
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
A mathematical approach to model diffusion properties of sedimentary rocks relevant to Sicily cultural heritage.
No full textCultural heritage vestiges represent complex physical systems, able to interact with the environment through continuous exchanges of heat and fluids (water, air). In this wide context, particular relevance is assumed by transport phenomena and diffusion of pollutant, vehiculated inside the considered structure by water itself. Interaction mechanisms can be considered at various observation scales, depending on the material provenance and on its geometry and location. Involved materials are commonly constituted by porous rocks - more or less altered - belonging to geological sedimentary formations, as limestone, calcarenite and travertine. Their appreciable porosity affects significantly liquid movements; on the other hand, relevant vacuole size and geometry are likely influenced by the interactions themselves. As a matter of fact, interconnected pores increase the proper vulnerability of the materials, causing a progressive deterioration of the cultural heritage due to the close liquid-rock relations through capillarity absorption as well as gravity movements. This contributes to enlarge the whole cultural heritage risk, imposing quick and skill interventions in order to mitigate the endangerment for progressive intrusions of water-pollutant complexes. In fact, the principal aim is the protection of vestiges by means of protective products, the efficiency of which can be tested by the integration of innovative techniques and methods.
In the described circumstances, analyses of transport and diffusion seem to be fundamental for understanding the mechanism of deterioration processes and the remedial actions to prevent the decay of the cultural heritage. In this paper Authors summarize integrated experiences already performed on samples, building materials and archaeological sites of Sicily, pointing the attention to temples, tombs and other ancient remains belonging to Sicilian Aeneolithic, Greek and Baroc periods. In detail, the integrated physical techniques were X-Ray Diffractometry (XRD), X-Ray Fluorescence (XRF), Hg Porosimetry, SEM analyses, Magnetic Resonance Relaxometry (MRR), Magnetic Resonance Imaging (MRI) and X-Ray CT imaging. Applied in situ equipments were portable geophysical instruments for non-destructive prospecting. Absorption kinetics studies and internal micro-porosity surveys on samples, both through MRI and X-ray CT, were performed too, leading to preliminary interpretations of porosity and diffusion features. The entirety of measures have given a first picture of the liquid intrusion in porous rocks, well depicted by imaging elaboration procedures and sets of diagrams illustrating the physical phenomena.
A notable improvement toward the proper rock knowledge could be represented by considering the pollution source features as well as the different physical-chemical interactions of liquids/contaminants with the mean. Indeed, the phenomena are relatively complex, especially in quantifying the effects of diffusion processes. Moreover, a strong consequential inaccuracy must be considered due to insufficient geometrical considerations on the single components of the system (i.e., geological layers and/or granulometric anisotropy). Therefore, a reliable step has to be represented by analytic solutions of these mechanisms, taking into account non-stationary phenomena too, occurring in fractured rocks. Furthermore, the intrinsic properties of the considered system (sample, archaeological site, quarry) can lead to a more complicated representation of the processes, worsening the correct modeling of the liquid/pollutant flow. Thus, adopted solutions should be essentially of numerical kind, they being conditioned by the model calibration by statistical analysis between calculated and measured values. Discretization and modeling in meshes of pixels and voxels, referred to easily workable matricial numerical values, concur to the elaboration of thematic and summarized representations, with the aid of dedicated software’s, also performing a likely depiction of the cultural heritage
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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