1,720,999 research outputs found
The phreatic water system of Vulcano, Aeolian Island: time-variations of chemical and isotopic parameters.
No full textChemical and isotopic compositions of the shallow groundwater system of Vulcano Island, Aeolian Archipelago, Italy: an update
No full textCold and thermal waters were sampled on Vulcano Island from shallow wells in June 1995, June 1996 and January-February 1997; additional samples refer to a thermal spring, meteoric water from domestic cisterns and local seawater.
The chemical and isotopic (hydrogen, oxygen, tritium and strontium in water, and sulfur and oxygen in sulfate ions) compositions measured in the samples showed that: 1) the shallow hydrothermal system is formed by the mixing of waters of meteoric origin and various ages with crater-type fumarolic steam and gases (phreato-volcanic waters), with water rising from the geothermal reservoir expected to exist at depth (sulfate-chloride waters), and with steam and gases released from the geothermal reservoir itself (steam-heated waters); 2) a major seawater contribution occurs only in water from a well exploited in the Togo-Togo Camping, that is located very close to the shoreline; 3) dissolved sulfate mostly derives from oxidation of fumarolic/magmatic sulfur species, with minor sporadic contributions from seawater or from dissolution of secondary anhydrite; and 4) major changes in the chemical and isotopic compositions of the bulk groundwater system were not observed during the study period, and the appreciable variations in waters from few wells may be interpreted as due to changes in the mixing proportions of the endmembers or to direct rainwater dilution.
Based on the present study and previous ones from literature, an updated geochemical model is proposed for the groundwaters system at Vulcano and its relations with the crater and beach fumarolic fluids
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Chemical and isotopic compositions of water and dissolved sulfate from shallow wells on Vulcano Island, Aeolian Archipelago, Italy
No full textTwenty-two cold and thermal waters from shallow wells sampled in June 1995 in the Vulcano Porto area, Vulcano Island, were analyzed for major and minor chemical constituents, oxygen and hydrogen isotopes and tritium contents, and sulfur isotopes in the dissolved sulfate. The sulfur isotopic composition of the dissolved sulfate ranges between +0.6 and +6.5% (mean +3.7 +- 1.7%), and is interpreted as deriving mainly from fumarolic SO2 undergoing oxidation in deep and shallow aquifers, with possible minor contributions from oxidation of H2S. Dissolution of secondary anhydrite may have been a minor source of the
isotopically heavy aqueous sulfate in the cold groundwaters. The chemical and isotopic features of the waters support previous interpretative hydrologic models of Vulcano Porto, which comprise a number of aquifers fed basically by two major end-members, i.e. meteoric water and crater-type fumarolic inputs, the latter in the form of absorbed emissions or condensate. These data, along with the sulfur isotopes of aqueous sulfate, exclude involvement of seawater in the recharge of the groundwater system of the island
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