1,721,004 research outputs found
Influence of the “Host-guest” interactions on the mobility of Genistein/Beta Cyclodextrin inclusion complex
No full textNeutron radiography for the characterization of porous structure in degraded building stones
Full text linkAs it is well known, the porous structure of stones can change due to different degradation processes that modify the characteristics of freshly quarried blocks. Their knowledge is fundamental for predicting the behavior of stones and the efficacy of conservative treatments. In this context, neutron radiography is a useful tool not only to visualize the structure of porous materials, but also to evaluate the degree of degradation and surface modifications resulting from weathering processes. Furthermore, since thermal neutrons suffer a strong attenuation by hydrogen, this technique is effective in order to investigate the amount of absorbed water in building materials. In the present work, we report a neutron radiography investigation of limestones cropping out in the South-Eastern Sicily and widely used as building stones in Baroque monuments of the Noto Valley. The analyzed samples have been submitted to cyclic salt crystallization that simulate degradation processes acting in exposed stones of buildings. The obtained results demonstrate the interest of neutron radiography to better understand deterioration processes in limestones and to acquire information useful for restoration projects. © 2014 IOP Publishing Ltd and Sissa Medialab srl
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
New insights into the structure and function of the prokaryotic communities colonizing plastic debris collected in King George Island (Antarctica): Preliminary observations from two plastic fragments
No full textIn Antarctic regions, the composition and metabolic activity of microbial assemblages associated with plastic debris (“plastisphere”) are almost unknown. A macroplastic item from land (MaL, 30 cm) and a mesoplastic from the sea (MeS, 4 mm) were collected in Maxwell Bay (King George Island, South Shetland) and analyzed by Fourier transform infrared spectroscopy in attenuated total reflectance geometry (FTIR-ATR), which confirmed a polystyrene foam and a composite high-density polyethylene composition for MaL and MeS, respectively. The structure and function of the two plastic-associated prokaryotic communities were studied by complementary 16S ribosomal RNA gene clone libraries, total bacterioplankton and culturable heterotrophic bacterial counts, enzymatic activities of the whole community and enzymatic profiles of bacterial isolates. Results showed that Gamma- and Betaproteobacteria (31% and 28%, respectively) dominated in MeS, while Beta- and Alphaproteobacteria (21% and 13%, respectively) in MaL. Sequences related to oil degrading bacteria (Alcanivorax,Marinobacter) confirmed the known anthropogenic pressure in King George Island. This investigation on plastic-associated prokaryotic structure and function represents the first attempt to characterize the ecological role of plastisphere in this Antarctic region and provides the necessary background for future research on the significance of polymer type, surface characteristics and environmental conditions in shaping the plastisphere
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
Application of fractal models to ancient ceramics: structural and technological aspects
No full textIn this work we present the result of a research finalized to put forth new elements about technology of the pottery production in the Middle Bronze Age in Sicily (15th-13th century BC) by using fractal models. Recently, this approach successfully applied to study Hellenistic-Roman pottery from Syracuse (Sicily, Southern Italy) [Barbera, 2013], evidenced the efficiency of fractal geometry in description of the meso and micro scale structure of the ceramics in order to obtain technological informations.
The lack of archaeometric data about the pottery production of Prehistoric Sicilyrepresents the main problem currently conditioning future advances in archaeological research.
The characterization of ancient ceramics is complex due to the heterogeneity of the materials on different scales and to the coexistence of amorphous and crystalline phase in the same sample. For these reason, a complete structural characterization could be achieved through investigation at different scales of observation.
A group of Middle Bronze Age pottery from the cave site of Grotte di Marineo (Licodia Eubea, Catania, Italy) was selected, as case study. The sampled potteries belong to the three chronological sub-phases in which the local Bronze Age can be divided. The goal of this study is to acquireinformation about the evolution of technological aspects of pottery manufacture over the time. In particular we investigate the firing temperature and technological production processes.
The mesoscopic structure of the samples has been investigated through small angle neutron scattering (SANS), in order to obtain information about the size and surface characteristics of the aggregates of minerals and voids. These parameters are reported in literature dependent to the firing technology used in the production process [Botti, 2006]. All the obtained results were interpreted in the framework of fractal model. Data have been also compared with the mesoscopic parameters and fractal dimension extracted for clay sediments typical of the Sicilian area and fired under controlled conditions [Barone, 2009]. The observed agreement between the features of reference and archeological samples allowed us to estimate the maximum firing temperature of the latter. Barbera et al, J Arch Sci, 40: 983–991, 2013.
Barone et al., J Appl Phys, 106: 054904, 2009.
Botti et al., J. Arch Sci, 33: 307-319, 2006
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
