1,720,963 research outputs found
Congruence between molecular and morphological systematics of Alpine non-biting midges (Chironomidae, Diamesinae)
No full textIn mountain regions, climate change is resulting in glacial retreat, causing biodiversity loss in glacial-fed streams (kryal habitat). Diamesa species (Diptera Chironomidae), the main colonizers of the kryal in the Alps, are the aquatic insects more threatened by extinction. In recent years, DNA barcoding was successfully adopted to delimit species of chironomids and provided species identification. We highlighted that for the Diamesa genus, inconsistencies remain between identification on a morphological and molecular basis, mainly within cinerella and zernyi groups, raising doubts about the validity of head colour as a good diagnostic taxonomic character. Molecular phylogeny reconstruction based on mitochondrial (cytochrome oxidase subunits I and II) and one nuclear (ribosomal 18S rRNA) markers revealed that D. bohemani and D. zernyi on one hand, and D. cinerella and D. tonsa on the other hand, represent populations of the same species. Divergence times suggested that the radiation of these alpine species seems to have been driven by the climatic events with the alternation of glacial periods that happened in the Pliocene and Pleistocene. The initial separation of the oriental species D. steinboecki seems to be due to the tectonic movements of the Periadriatic fault system that probably favoured the emergence of lakes and streams, successively colonized by D. steinboecki. This study raises important concerns, from the validity of diagnostic characters used today to identify larval types up to the uncertainty about how many species of Diamesa inhabit the European Alps and what their fate will be within the scenario of climate change
First-Principles Simulations of Lithium Melting: Stability of the bcc Phase Close to Melting
No full textWe report large-scale first-principles simulations of melting of four different phases of Li at pressures ranging from 0 to 50 GPa. We find excellent agreement with existing experimental data at low pressures, and confirm that above 10 GPa the melting line develops a negative slope, in parallel to what occurs for Na at 30 GPa. Surprisingly, our results indicate that the melting temperature of the bcc phase is always higher than that of fcc Li, suggesting the intriguing possibility of the existence of a narrow field of bcc stability separating the fcc and liquid phases, as predicted by Alexander and McTague [Phys. Rev. Lett. 41, 702 (1978)]
A decision support system to assess the operational safety and economic benefits of risk-based inspection implementation strategies
No full textThe modern industrial landscape is defined by increased competition, shorter response times, lower costs, and more reliable processing to meet customer demands. As a result, it has gained traction worldwide, and the necessity to undergo radical digital transformations in how they deal with processes. Specifically, it is receiving great relevance to the construction of specific decision support systems (DSSs) to help monitor industrial systems with a data-driven analytic approach, aiming to maximise reliability and efficiency. Maintenance is one of the most investigated processes based on risk-driven inspection. The Risk-Based Inspection (RBI) procedure, widely consolidated in the scientific field thanks to the publication of the API RP 581 manual of the American Petroleum Institute, is one of the most used procedures in the oil and gas sector to carry out risk assessments of the integrity of industrial components. It forms the basis for developing inspection plans within which the components to be inspected are prioritised based on the associated risk of failure. The use of non-intrusive inspection methodologies, based on non-destructive testing techniques, is incorporated into the assessment as an alternative to other traditional inspection strategies based on direct inspection. These techniques may help to reduce the number of scheduled plant shutdowns and the associated cost due to production loss. This research aims to develop a decision support system (DSS) based on the guidelines of the RBI procedure that is easy to use and open to access to support decisions in a cost-benefit analysis of the maintenance process. The system was developed focusing on a real plant, assessing the operational and financial risk of the shell and tube heat exchanger. The data used to implement the procedure in the system were provided by the company SGS specialised in industrial components’ certification and inspection. The current assessment has been performed for the damage mechanisms that affect the considered equipment: thinning, external corrosion, and CUI. All of the referred damage mechanisms are corrosion-based. None of the other multiple damage mechanisms that could affect the industrial equipment has been considered in this work
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
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