1,720,972 research outputs found
Conservation of cultural stones: relationship among texture, thermal ageing and consolidation strategies in white Apuan marbles
Get PDFA major problem in the conservation of stone materials concerns durability and the use of compatible and
efficacy conservation treatments. Among cultural stones, white Apuan marble stands out for its wide diffusion in built
environment; thus, the study of its decay and the recognition of smart solution for its conservation is a quite relevant
issue. In spite of an aesthetical homogeneity, white marbles exhibit a range of textural features able to influence their
durability. The aims of this study are therefore to evidence the relationship between decay and textural features in
marbles, and to test the efficacy of some innovative nanostructured products in comparison to ethyl-silicate. Ten white
marbles from different Apuan Alps quarrying areas, characterized by a range of textural features, were analyzed.
Preliminary, textural, mineralogical and chemical analysis have been performed by petrographic, XRD, and XRF
analyses; physical properties were determined by both capillarity and water absorption by total immersion tests on
specimens. After an initial drying at 60±5°C, specimens were artificially aged by thermal stresses (cycles at 110°C,
110°C and cooling in water, 250°C, and 550°C). The comparison of physical parameters before and after thermal
stresses allows evaluating the influence of some textural factors (especially grain boundaries and mean grain size) on
the decay. Artificially thermal damaged samples were subsequently treated with two nanostructured products, nano-lime
and nano-silica, and with ethyl-silicate, to compare the efficacy of innovative consolidants in respect to a traditional one.
The efficacy was evaluated on the basis of water absorption behavior of marbles before and after treatments. The study
evidenced better performances of nano-silica in respect to nano-lime, even ethyl-silicate confirmed its high effectiveness
in consolidating marbles regardless their textural features
Escrezione urinaria di 1-idrossipirene in addetti all'asfaltatura delle strade esposti ad idrocarburi policiclici aromatici
No full textPerformance of an olive orchard managed by coppicing for 20 years
No full textThe pruning of olive (Olea europaea L.) trees is an expensive practice in olive growing. In this paper we report on the 20 year performance of an olive orchard managed by coppicing. This alternative method was developed to minimize pruning costs and simplify orchard management. Trees were planted at 6 x 6 m distance in spring 1969 and trained to a vasebush by regular annual pruning until spring 1980, when the orchard was divided into 10 plots of about 20 trees each and all trees in one plot were cut off at ground level. In the following years coppicing was extended to one additional plot per year until 1989. In 1990 the plot first coppiced in 1980 was coppiced again to begin a second cycle of coppicing. During the 10 years of each cycle, pruning was limited to the elimination of a few suckers in the centre of the canopy on the third year after coppicing. Thus, the coppiced system required a maximum of 14 min/plant of pruning over 10 years corresponding to 6.5 h ha(-1) year(-1) of unskilled labour. The onset of fruit production occurred the third or the fourth year after coppicing. Fruit yield of the coppiced orchard was 85% of that of an adjacent orchard trained to vasebush (control). Alternate bearing was less in the coppiced orchard than in the control orchard. No effect of coppicing was found on fruit or oil quality, or occurrence of pests and diseases. The coppicing method is not only suitable to rejuvenate old olive trees but also to manage orchards sustainably at a minimum cost for pruning. The main disadvantage is the unsuitability for mechanical harvesting by trunk shakers because the plant canopy is formed by multiple stems
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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
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