1,720,982 research outputs found
Perfiles verticales de metales en sedimentos del Río Uruguay, Argentina
No full textFil: Tatone, Leandro Martín. Laboratorio de Química Ambiental y Biogeoquímica. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Bilos, Claudio. Laboratorio de Química Ambiental y Biogeoquímica (LAQAB). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Skorupka, Carlos Norberto. Laboratorio de Química Ambiental y Biogeoquímica (LAQAB). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Colombo, Juan Carlos. Laboratorio de Química Ambiental y Biogeoquímica (LAQAB). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; Argentin
Dinámica de metales pesados en la laguna Inés (Bahía de Ñandubaysal, Río Uruguay)
No full textFil: Bilos, Claudio. Laboratorio de Química Ambiental y Biogeoquímica (LAQAB). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Tatone, Leandro Martín. Laboratorio de Química Ambiental y Biogeoquímica (LAQAB). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Skorupka, Carlos Norberto. Laboratorio de Química Ambiental y Biogeoquímica (LAQAB). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Colombo, Juan Carlos. Laboratorio de Química Ambiental y Biogeoquímica (LAQAB). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; Argentin
Airborne PAHs and PCBs along a coastal, urban-industrial gradient in Rio de la Plata Estuary, Argentina
Full text linkFil: Astoviza, Malena Julia. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; ArgentinaFil: Migoya, María Carolina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; ArgentinaFil: Morrone, Manuel. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; ArgentinaFil: Bilos, Claudio. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; ArgentinaFil: Colombo, Juan Carlos. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; Argentin
Trace metals in settling particles from the sewage impacted Buenos Aires coastal area in the Río de la Plata estuary, Argentina
Full text linkSediment traps deployed in Buenos Aires sewage outfall area collected a substantial amount of material (average mass flux 22 ± 12 g cm 2 year−1) with very high metal concentrations, mostly in the range of hazardous exposition for organisms (Zn: 138–671, Cu: 41–273, Cr: 44–255 and Pb: 26–260 μg g−1). The combination of high mass fluxes and concentrations results in huge metal fluxes (0.005–0.7 to 3.6–31 g m−2 day−1 for minor elements and Fe, respectively). Metal concentrations were correlated to the total mass flux and total organic carbon but with different trends for redox-sensitive Fe and Mn (negative) and anthropogenic elements (positive). This reflects the key role of organic discharges promoting anoxia with Fe and Mn evasion, and also contributing toxic metals.Fil: Tatone, Leandro Martín. Universidad Nacional de la Plata. Facultad de Cs.naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bilos, Claudio. Universidad Nacional de la Plata. Facultad de Cs.naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Skorupka, Carlos Norberto. Universidad Nacional de la Plata. Facultad de Cs.naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Colombo, Juan Carlos. Universidad Nacional de la Plata. Facultad de Cs.naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
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
Heavy metal contents in the most productive Argentinean Humid Pampa soils
No full textArgentinean Humid Pampa topsoil samples from sites with different land use patterns were analysed. Texture was dominated by fines (silt+clay > 50%) with high total organic carbon content (2.8 ± 1.8%), particularly in finer soils (3.7?9.9% to 0.99% in sandy soils). Carbon:nitrogen relationship was relatively homogeneous (13.9 ± 3.6%) pointing to a dominant contribution of terrestrial plant detritus. Heavy metal concentrations were low (Fe: 1.77 ± 0.50%; Mn: 446 ± 171; Zn: 48.4 ± 19.5; Cu: 17.6 ± 6.0; Pb: 10.0 ± 4.8; Cr: 7.2 ± 1.8; Ni: 6.1 ± 1.7; Cd: 0.05 ± 0.03 μg g-1) and spatially homogeneous ( 0.05). Heavy metal enrichment factors were low (0.07?2.28) indicating a natural origin.Fil: Bilos, Claudio. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; ArgentinaFil: Tatone, Leandro Martín. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Skorupka, Carlos Norberto. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; ArgentinaFil: Astoviza, Malena Julia. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; ArgentinaFil: Romero, Camila Lucía. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; Argentina. Ministerio de Ciencia. Tecnología e Innovación Productiva. Agencia Nacional de Promoción Científica y Tecnológica; ArgentinaFil: Colombo, Juan Carlos. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentin
Comparative approach for trace metal risk evaluation in settling particles from the Uruguay River, Argentina: enrichment factors, sediment quality guidelines and metal speciation
Full text linkThe source and potential risks of trace metals in settling material collected with sediment traps in the Uruguay River were evaluated utilizing enrichment factors (EF), sediment quality guidelines (SQG) and speciation using a 4-step sequential extraction procedure. The total organic carbon content of the settling material was relatively high and homogeneous (2.5 ± 0.3 %) and showed no correlation with the metal concentrations. Total trace metal concentrations decrease from Fe (48,969 ± 7380 µg g−1), Mn (1859 ± 233 µg g−1), Zn (84 ± 7.6 µg g−1), Cu (56 ± 6.9 µg g−1), Cr (19 ± 2.7 µg g−1), Ni (16 ± 2.0 µg g−1) and Pb (13 ± 1.2 µg g−1). The average EF of Zn, Cr, Ni and Pb are below 1.5 indicating natural sources, whereas those of Cu and Mn are consistently higher (EF > 2) insinuating some anthropogenic influence. Consistently, Cu concentrations duplicated the SQG (35.7 μg g−1) suggesting that adverse biological effects may be observed occasionally. However, speciation results revealed that most metals are associated with the residual fraction, strongly linked to the mineral matrix, and therefore unavailable to aquatic organisms. The sole exception is Mn which is mainly found in the non-residual fractions (∑F1 − F3 = 82 %). Trace metal mobility/bioavailability decreased from Mn (82 %) ≫ Pb (37 %) > Cr (26 %) ~ Ni (25 %) > Zn (20 %) > Cu (14 %) > Fe (10 %). These results demonstrate the utility of metal speciation studies to assess the real risk for aquatic organisms of high Cu concentrations, but associated to relatively immobile fractions of reduced bioavailability.Fil: Tatone, Leandro Martín. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bilos, Claudio. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; ArgentinaFil: Skorupka, Carlos Norberto. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; ArgentinaFil: Colombo, J. C.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentin
- …
