1,721,342 research outputs found
Shape matters: long-range transport of microplastic fibers in the atmosphere
Full text linkDeposition of giant microplastic particles from the atmosphere has been
observed in the most remote places on Earth. However, their deposition patterns
are difficult to reproduce using current atmospheric transport models. These
models usually treat particles as perfect spheres, whereas the real shapes of
microplastic particles are often far from spherical. Such particles experience
lower settling velocities compared to volume-equivalent spheres, leading to
longer atmospheric transport. Here, we present novel laboratory experiments on
the gravitational settling of microplastic fibers in air and find that their
settling velocities are reduced by up to 76% compared to spheres of the same
volume. An atmospheric transport model constrained with the experimental data
shows that shape-corrected settling velocities significantly increase the
horizontal and vertical transport of particles. Our model results show that
microplastic fibers of about 1 mm length emitted in populated areas can reach
extremely remote regions of the globe, including the High Arctic, which is not
the case for spheres. We also calculate that fibers with lengths of up to 100
{\mu}m settle slowly enough to be lifted high into the stratosphere, where
degradation by ultraviolet radiation may release chlorine and bromine, thus
potentially damaging the stratospheric ozone layer. These findings suggest that
the growing environmental burden and still increasing emissions of plastics
pose multiple threats to life on Earth
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
Air Pollution Import to and Export from East Asia
No full textContinued rapid industrialization is expected to make East Asia the largest source region for air pollution in the coming decades. This chapter reviews the import and export of air pollutants, mainly carbon monoxide and ozone, by long-range transport to and from East Asia. Air pollutant sources and transport characteristics dominated by the monsoon regime over Northeast and Southeast Asia are summarized. Over Northeast Asia both import and export of air pollution contribute significantly to the intercontinental transport of pollution. Trans-Eurasian transport of air pollution by westerly flows from Europe to Northeast Asia, and trans-Pacific transport of Northeast Asian pollution to the Pacific and North America have been verified by both observations and model studies. The influence of Siberian forest fires on pollutants over Northeast Asia has also been clearly identified. Over continental Southeast Asia, import of air pollution occurs mainly from source regions over the Indian subcontinent during the summer monsoon and from Northeast Asia during the early winter monsoon. Biomass burning within the region, however, strongly dominates regional pollution. The transoceanic export of air pollution from Southeast Asian biomass burning is known to be one of the most significant sources of ozone and CO over the North Pacific in the springtime
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
Lagrangian analysis of ozone trends at selected receptor sites in the Northern Hemisphere
No full textkoamabayili/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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