1,721,174 research outputs found
The precious "scientific heritage" of Mariano Valenza: the unknown history of Ludovico Sicardi and the birth of the modern volcanology
No full textMariano Valenza was an important scientific figure of the geochemical community and a person characterized by his great intellect, diplomacy and human qualities. Sadly, he passed away in July of 2018, leaving a great void. He left us a precious treasure for all the geochemists involved in volcanology: the story and the memory of Ludovico Sicardi. Indeed, Valenza carefully preserved in his office, for a long time, four boxes containing the scientific material belonged to Ludovico Sicardi. As often happens, a little by chance, the precious material returned to light thirty-five years later, on the 20th of April 2018, and was donated to the Museum of Mineralogy of Palermo. It is nowadays subject of study and cataloging by the volunteers of the Associazione Naturalistica Geode. The “scientific treasure” consists of the personal field-equipment of Sicardi, glassware, copies of the scientific articles, many old maps of volcanic areas, several historical photos of Vulcano and Solfatara. Among all these findings, several manuscript notes and three important unpublished researches about Vulcano, Vesuvio and Campi Flegrei. Who was Ludovico Sicardi? Sicardi was a chemist and a pharmacist, who was passionate about volcanoes and, in particular, enraptured by the island of Vulcano (Eolie - Sicily). During his several field trips in Vulcano, he observed and described the fumarolic field on systematic basis, measuring the temperatures and recording their variations over time (Sicardi, 1973). He was the first to perform chemical analysis of fluids emitted by fumaroles in Vulcano Island and Solfatara. Furthermore, he was the former to suppose the coexistence of SO2 and H2S in fumarolic discharges, which by that time was considered to be impossible. Also, he succeeded in measuring their ratio by developing an in situ method that chemically separate the S-gaseous species. This method was based on the sampling of fumarolic fluids using a glass flask that contained a NH4OHAgNO 3solution, with the aim to absorb the soluble acid gases (CO2, SO2 and HCl) and precipitate H2S as an insoluble Ag2S (Sicardi, 1955). Based on his remarkable scientific production, Sicardi can be considered as a precursor of the modern Volcanology and a pioneer of the volcanic monitoring techniques.We are extremely grateful to Mariano Valenza for giving us this fascinating story
Volcanic Lakes in Africa: The VOLADA_Africa 2.0 Database, and Implications for Volcanic Hazard
Full text linkVolcanic lakes pose specific hazards inherent to the presence of water: phreatic and
phreatomagmatic eruptions, lahars, limnic gas bursts and dispersion of brines in the
hydrological network. Here we introduce the updated, interactive and open-access
database for African volcanic lakes, country by country. The previous database VOLADA
(VOlcanic LAke DAta Base, Rouwet et al., Journal of Volcanology and Geothermal Research,
2014, 272, 78–97) reported 96 volcanic lakes for Africa. This number is now revised and
established at 220, converting VOLADA_Africa 2.0 in the most comprehensive resource for
African volcanic lakes: 81 in Uganda, 37 in Kenya, 33 in Cameroon, 28 in Madagascar, 19 in
Ethiopia, 6 in Tanzania, 2 in Rwanda, 2 in Sudan, 2 in D.R. Congo, 1 in Libya, and 9 on the
minor islands around Africa. We present the current state-of-the-art of arguably all the African
volcanic lakes that the global experts and regional research teams are aware of, and provide
hints for future research directions, with a special focus on the volcanic hazard assessment.
All lakes in the updated database are classified for their genetic origin and their physical and
chemical characteristics, and level of study. The predominant rift-related volcanism in Africa
favors basaltic eruptive products, leading to volcanoes with highly permeable edifices, and
hence less-developed hydrothermal systems. Basal aquifers accumulate under large
volcanoes and in rift depressions providing a potential scenario for phreatomagmatic
volcanism. This hypothesis, based on a morphometric analysis and volcanological
research from literature, conveys the predominance of maar lakes in large monogenetic
fields in Africa (e.g. Uganda, Cameroon, Ethiopia), and the absence of peak-activity crater
lakes, generally found at polygenetic arc-volcanoes. Considering the large number of maar
lakes in Africa (172), within similar geotectonic settings and meteoric conditions as in
Cameroon, it is somewhat surprising that “only” from Lake Monoun and Lake Nyos fatal CO2
bursts have been recorded. Explaining why other maars did not experience limnic gas bursts
is a question that can only be answered by enhancing insights into physical limnology and
fluid geochemistry of the so far poorly studied lakes. From a hazard perspective, there is an
urgent need to tackle this task as a community
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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