1,720,982 research outputs found
Temporal evolution of gas-phase polychlorinated biphenyls in the Venice lagoon atmosphere
No full textTransport of Gas-Phase Polycyclic Aromatic Hydrocarbons to the Venice Lagoon
No full textConcentrations of gas-phase polycyclic aromatic hydrocarbons
(PAHs) were studied over one year at two sites of
the Venice lagoon (designated Marine and Industrial)
and at a mainland station (designated Rural) in Italy. Average
åPAH concentrations, calculated as sum of 16 PAHs, at
Marine are about three and five times lower than those at
Industrial and Rural, respectively. The seasonal trends,
the temperature-PAH relationship, and principal component
analysis indicate that at Industrial and Marine sites
several local sources (vehicle and industrial emissions,
etc.) could be the PAH sources in the warmer months,
whereas in the colder months the main PAH sources could
alternate between vehicle emissions and residential
heating. At Rural the main PAH sources are: vehicle
emissions in the spring and autumn; vehicle emissions,
field burning, and wood combustion in the summer; and
vehicle emissions and fuel consumption for residential heating
in the winter. To evaluate the contribution from different
sources to the Venice Lagoon air, horizontal fluxes of PAHs
have been obtained. The estimated annual flux of PAHs
is about 9 times greater at Industrial (193.5 mg m-2 y-1) than
at Marine (20.6 mg m-2 y-1). These results show that
study of the chemical contamination of the Venice atmosphere
must take into account the PAH flux derived from marine
sources as well as the continental input
Distribution of particulate- and vapour-phase polychlorobiphenyls and polycyclic aromatic hydrocarbons in the atmosphere of the Venice Lagoon
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Determination of Polychlorobiphenyls and polycyclic aromatic hydrocarbons in the atmospheric aerosol of the Venice Lagoon
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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
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