1,721,202 research outputs found
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
Peat bog records of dust deposition over the last 2000 years in the Dolomites (NE Italian Alps)
No full textPeat bog records of dust deposition over the last 2000 years in the Dolomites (NE Italian Alps)
No full textMapping environmental suitability for anthrax reemergence in the Arctic
Full text linkRecent studies have raised concerns about the potential reemergence of infectious diseases in Arctic regions associated with warming temperatures. Among these, particular attention has been devoted to anthrax, as a consequence of the outbreak that occurred in the Russian Yamalo-Nenets peninsula in 2016. Understanding how environmental change might influence the diffusion of this pathogen could allow informed decisions to prevent further zoonotic or epidemic episodes. To that end, the present study aims to identify and investigate the driving variables that may favor anthrax transmission within the Arctic, in order to build environmental niche maps describing the future suitability of these regions for the pathogen. To do so, we use the MaxEnt statistical learning tool informed by Arctic-specific variables, such as reindeer herd distribution and active-layer variation. Because of the relative lack of reliable georeferenced information in these regions, the resulting potential distribution maps are to be considered preliminary, but they can already provide a first assessment tool for local communities living in potential risk areas. They also indicate areas in which additional investigation is needed to improve the reliability of environmental niche modeling, hence the accuracy of risk mapping and the usefulness to Arctic communities
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
Permafrost dynamics and the risk of anthrax transmission: a modelling study
Full text linkA recent outbreak of anthrax disease, severely affecting reindeer herds in Siberia, has been reportedly associated to the presence of infected carcasses or spores released from the active layer over permafrost, which is thawing and thickening at increasing rates, thus underlying the re-emerging nature of this pathogen in the Arctic region because of warming temperatures. Anthrax is a global zoonotic and epizootic disease, with a high case-fatality ratio in infected animals. Its transmission is mediated by environmental contamination through highly resistant spores which can persist in the soil for several decades. Here we develop and analyze a new epidemiological model for anthrax transmission that is specifically tailored to the Arctic environmental conditions. The model describes transmission dynamics including also herding practices (e.g. seasonal grazing) and the role of the active layer over permafrost acting as a long-term storage of spores that could be viable for disease transmission during thawing periods. Model dynamics are investigated through linear stability analysis, Floquet theory for periodically forced systems, and a series of simulations with realistic forcings. Results show how the temporal variability of grazing and active layer thawing may influence the dynamics of anthrax disease and, specifically, favor sustained pathogen transmission. Particularly warm years, favoring deep active layers, are shown to be associated with an increase risk of anthrax outbreaks, and may also foster infections in the following years. Our results enable preliminary insights into measures (e.g. changes in herding practice) that may be adopted to decrease the risk of infection and lay the basis to possibly establish optimal procedures for preventing transmission; furthermore, they elicit the need of further investigations and observation campaigns focused on anthrax dynamics in the Arctic environment
Diatoms in very-shallow pools of the site of community importance danta di cadore mires (South-Eastern Alps), and the potential contribution of these habitats to diatom biodiversity conservation
No full textMires are very selective habitats, and the colonisation by specifically adapted organisms makes them very important both for nature conservation and environmental education. They have, however, been threatened by different types of impacts. Our objective was to study diatoms in stations representative of the main typologies in the Site of Community Importance IT3230060 "Danta Mires", also to produce data for a management plan in the frame of a Life Project. Five shallow pools within different mountain mires were sampled in summer 2005 and morphologically and physicochemically characterized. The sampled sites cover a rather wide pH and TDS content gradient with very low nitrate and silica values. Diatoms were found to dominate in terms of numbers of taxa, followed by desmids, cyanoprokaryotes and filamentous green algae. In total, 86 diatom taxa, belonging to 35 genera, were found. As expected for acidic, low-mineralization waters the genera with the highest number of taxa were Eunotia and Pinnularia, followed by Encyonema, Cymbopleura, Gomphonema, and Nitzschia. The most frequent and abundant taxa were: Frustulia crassinervia, Nitzschia acidoclinata, Kobayasiella micropunctata, Encyonema neogracile, Brachysira brebissonii, Nitzschia perminuta, and Encyonema lunatum. Taxa abundant only in one or few sites were: Eunotia paludosa, Staurosira spinarum, Encyonopsis cesatii, and Achnanthidium minutissimum. Several rare taxa of special interest for their distribution and/or rarity could be found (e.g. Chamaepinnularia schauppiana, Cymbopleura incertiformis var. linearis, C. subapiculata, Eunotia lapponica, Microfissurata paludosa). On average, 17 taxa per site were found. The highest number (26) was found in a sediment sample taken in a site with special hydrochemical characteristics, and the minimum (11 taxa) in the sediment sample of the demolition materials dump mire. Diatom communities allowed characterising the mire pools studied as oligotrophic, acidic environments often affected by desiccation. On the basis of the autecology and distribution of the most frequent and abundant taxa, pH and hydroperiod appeared to be the most relevant environmental determinants. A striking result, also in view of eventual management consequences, was the very high proportion (72%) of rare and Red List taxa (including also species of the categories "Threatened with extinction", "Severely endangered", and "Endangered"). To preserve diatom biodiversity, these mires must be sheltered from uses other than recreational ones, and abrupt changes in hydrological regime and increases in nutrient input must be prevented. © 2011 J. Cramer in Gebr
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