1,720,957 research outputs found
Development and application of low-cost monitoring approaches for atmospheric ammonia, acid gases and ammonium aerosols
Full text linkAmmonia (NH3) is the major alkaline gas in the atmosphere, with around 90 % of the total anthropogenic emissions in Europe coming from agriculture-related sources. Following emission to the atmosphere, the neutralisation reaction
between NH3 and the acid gases sulfur dioxide (SO2), nitric acid (HNO3) and hydrochloric acid (HCl) produces secondary inorganic aerosols (ammonium nitrate (NH4NO3), ammonium sulfate ((NH4)2SO4) and ammonium chloride (NH4Cl)). With longer atmospheric lifetimes than the gases, the aerosols also contribute to transboundary pollution problems. The gases and aerosols are removed from the atmosphere by wet (in precipitation) or dry (direct uptake by vegetation and surfaces) deposition processes. Together, they can negatively impact the natural environment through the input of excess acidity and nutrient nitrogen and harm human health through the formation of aerosols that contributes to fine-mode particulate matter (PM2.5). They can also potentially influence climate change from the radiative forcing properties of the aerosols and the inputs of nitrogen that can alter the carbon cycle.
Monitoring data are necessary for assessing the spatial and temporal extent of pollution and as evidence to detect changes in pollutant concentrations in response to current and future policies to mitigate emissions of NOx, SO2 and
NH3. Combined with models, the concentration data are also used to estimate the different fractions of the total sulfur or nitrogen input and different chemical forms of the pollutants. Since the spatial and temporal patterns and
atmospheric behaviours of gases and aerosols differ, measurements therefore need to distinguish between the phases.
The development of simple, low-cost, time-integrated air sampling methods and their application in cost-efficient monitoring strategies to assess temporal, spatial and trends in the gas and aerosol pollutants in the UK and across
Europe is described. An active diffusion denuder method (DELTA®) and a passive sampler (ALPHA®) are implemented at a large number of sites (> 70) in the UK National Ammonia Monitoring Network (NAMN, established 1996) to measure NH3 with a monthly frequency. An extension of the DELTA® method provided additional, monthly measurements of particulate NH4+(for the NAMN)and of the acid gases (SO2, HNO3, HCl) and aerosol species (NO3-, SO42-, Cl-,Na+, Ca2+, Mg2+) for the UK Acid Gas and Aerosol network (AGANet, established 1999) at a subset of NAMN sites. The close integration of the two
networks demonstrated the cost-effectiveness of the DELTA® approach, which provided quality assured, concurrent speciated measurement data on multiple pollutants at multiple sites, and also simplicity of operation by a large network of site operators, some of whom have no technical or scientific background. The DELTA® approach and quality protocol developed in the UK networks was further applied to a pan-European NitroEurope (NEU) DELTA® network (20 countries: 2006 – 2010), with knowledge sharing and collaboration between multiple laboratories and research organisations.
Important features in the spatial variability and seasonality in the gas and aerosol components were captured in the UK and European networks. The gases, with shorter lifetimes in the atmosphere were found to be spatially more
heterogeneous, with a wider range of concentrations than their aerosol counterparts. Variations on a spatial scale were correlated with distributions and magnitude of emission sources, e.g. NH3 and NH4+ concentrations were highest in intensively farmed areas (e.g. East Anglia in eastern England, NAMN) and countries (e.g. the Netherlands, NEU DELTA®). In the UK, evidence is also presented of the contribution by long-range transboundary sources to enhancement of concentrations of NH4NO3 and (NH4)2SO4.
Distinct and contrasting seasonal cycles in the gas and aerosol phase components were established, important for identifying periods of pollution and for targeting abatement measures. The observed variations were attributed to seasonal changes in emission sources, atmospheric interactions and the influence of climate on partitioning between the gases and aerosols. For NH3, peaks in concentrations occur from increased volatilisation promoted by warm, dry conditions (summer) and also from agriculture-related emissions, with a main peak in spring and a smaller peak in autumn. Concentrations of SO2 were higher concentrations in winter (increased combustion), except in Southern Europe where the peak period was in summer. HNO3 concentrations were more complex, with small peaks in the seasonal cycle related to traffic and industrial emissions, photochemistry, meteorology and the influence of climate
on HNO3:NH4NO3 equilibrium. In comparison, the springtime peak in NH4NO3 was attributed to the reaction of a surplus of NH3 with HNO3 to form NH4NO3 in the aerosol phase under cooler, wetter conditions. A summertime peak in particulate SO42- was observed in Southern Europe, coinciding also with peaks in SO2, NH3 and HNO3 concentrations. While the high HNO3 concentrations suggests increased oxidative capacity for formation of H2SO4 (from SO2) and reaction with NH3 to form (NH4)2SO4, the absence of an NH4+ peak illustrates
the larger influence of the more abundant NH4NO3 in controlling the seasonality of particulate NH4+.
Important changes in the atmospheric concentrations and partitioning between the different gas and aerosol components were captured. The measurement data highlighted the dominance of NH3 and NH4NO3 in rural air, as the
emissions of SO2 and NOx continues to fall, against a backdrop of increasing NH3 emissions in the UK and across Europe since 2013. The observed shift in the form of NH4
+ aerosol from the stable (NH4)2SO4 to the semi-volatile
NH4NO3 is expected to maintain a larger fraction of the NH3 and HNO3 in the gas phase. NH4NO3 can act as a reservoir and release the gases in warm weather, which may partly explain the observed non-linearity between emissions and measured concentrations of NH3 in the UK data. The current and projected trends in the emissions of the gases SO2, NOx and NH3 suggest that NH3 and NH4NO3 can be expected to continue to dominate the inorganic pollution load over the next decades
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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