1,721,001 research outputs found
Gas-particle concentration and distribution of n-alkanes and polycyclic aromatic hydrocarbons in the atmosphere of Prato (Italy)
No full textAir samples were collected in an urban and industrialised area of Prato (Italy) during 2002, as part of a study to identify and measure
aliphatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs). Total concentrations of aliphatic hydrocarbons ranged between 170 and 282 ng m3 in the gas phase and from 48.9 to 276 ng m3 in the particulate phase. The average total PAH oncentrations
(gas + particulate) were 59.4 ± 26.5 ng m3, and both gas and particulate phase PAH concentrations decreased with increasing temperature. Source identification using diagnostic ratios and principal component analysis identified automobile traffic, in particular, the strong influence of diesel fuel burning, as the major PAH source. Gas-particle partition coefficients (Kp’s) of n-alkane and PAHs were well correlated with the sub-cooled liquid vapour pressure P0L and indicate stronger sorption of PAHs to aerosol particles compared with -alkanes
Enrichment of organic pollutants in the sea surface microlayer (SML) at Terra Nova Bay, Antarctica: influence of SML on superficial snow composition.
Full text linkConcentrations of dissolved and particle-associated n-alkanes, phthalates and polycyclic aromatic
hydrocarbons (PAHs) were measured in sea surface microlayer (SML) and sub-surface water (SSL) samples
collected in the coastal area of Terra Nova Bay, Antarctica, during the Austral spring 1998/1999. SML
concentrations of the selected organic compounds were higher than SSL values and the enrichment factors
were greater in the particulate phase than in the dissolved phase. During the same campaign, ‘‘fresh’’ snow
samples, collected at different altitudes (from sea level up to 2670 m) near the coast on Mt Melbourne,
immediately after a snowy event, were analysed in order to provide more information on air/sea exchange
processes. The same classes of organic compounds found in sea water were also present in ‘‘fresh’’ snow
samples. The surfactant fluorescent organic matter (SFOM), adsorbed on the microdrop aerosol surface,
could be considered the main constituent of the enrichment and the carrier at higher altitudes of organic
compounds. In fact, hydrocarbons (n-alkanes and PAHs), which are not surfactants like phthalates, could
interact with SFOM and follow the same fate
The use of levoglucosan for tracing biomass burning in PM2.5 samples in Tuscany (Italy)
No full textLevoglucosan was present in all samples and its concentrations showed a pronounced annual cycle with maximum levels in the cold season. The annual percentage of ratios of levoglucosan to OC ranged from 0.04 to 9.75% evidencing a major contribution of biomass burning to the aerosol OC during the winter. In the urban-background site, OC was strongly correlated with EC in winter, suggesting that the major fraction of OC was generated as primary particles along with EC. A background levoglucosan component
showed that biomass burning was continuously taking place in all the investigated sites. The biomass burning contribution to the Tuscany aerosol was made up of a background component and an additional component during winter probably due to wood burning for domestic heating
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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