74,780 research outputs found
Supplement to: Air concentrations of polybrominated diphenyl ethers (PBDEs) in 2002-2004 at a rural site in the Great Lakes
Atmospheric PBDEs were measured on a monthly basis in 2002-2004 at Point Petre, a rural site in the Great Lakes. Average air concentrations were 7.0 ± 13 pg m**-3 for the sum of 14BDE (excluding BDE-209), and 1.8 ± 1.5 pg m**-3 for BDE-209. Concentrations of 3 dominant congeners (i.e., BDE-47, 99, and 209) were comparable to previous measurements at remote/rural sites around the Great Lakes, but much lower than those at urban areas. Weak temperature dependence and strong linear correlations between relatively volatile congeners suggest importance of advective inputs of gaseous species. The significant correlation between BDE-209 and 183 implies their transport inputs associated with particles. Particle-bound percentages were found greater for highly brominated congeners than less brominated ones. These percentages increase with decreasing ambient temperatures. The observed gas/particle partitioning is consistent with laboratory measurements and fits well to the Junge-Pankow model. Using air mass back-trajectories, atmospheric transport to Point Petre was estimated as 76% for BDE-47, 67% for BDE-99, and 70% for BDE-209 from west-northwest and southwest directions. During the same time period, similar congener profiles and concentration levels were found at Alert in the Canadian High Arctic. Different inter-annual variations between Point Petre and Alert indicate that emissions from other regions than North America could also contribute PBDEs in the Arctic. In contrast to weak temperature effect at Point Petre, significant temperature dependence in the summertime implies volatilization emissions of PBDEs at Alert. Meanwhile, episodic observations in the wintertime were likely associated with enhanced inputs through long-range transport during the Arctic Haze period
Comparing Protonolysis and Transmetalation Reactions: Microcalorimetric Studies of C–AuI Bonds in [AuRL] Complexes
Producción CientíficaThe protonolysis of C–Au bonds in [AuRL] organometallic complexes
has been studied by calorimetry for twelve R groups. The experimental data
have been combined with DFT calculations to obtain Bond Dissociation Energy
values (BDE). The C–Au BDE values show a good correlation with the corresponding
isolobal C–H BDE values. The heat released in the protonolysis of
[AuRL] has also been measured for R = Ph and L = P(OPh)3, PPh3, PMe3, PCy3,
and IPr, and these values strongly depend on the trans influence of L because of the
mutual destabilization of the L–Au and Au–C bonds. The enthalpy of the
transmetalation reactions [AuR(PPh3)] + SnIBu3 → [AuI(PPh3)] + SnRBu3 for
seven R groups have been measured and compared with the corresponding
[AuR(PPh3)] protonolysis.Ministerio de Economía, Industria y Competitividad (Project CTQ2016-80913-P)Junta de Castilla y León (Project VA 051P17
Fluid/gravity correspondence: A nonconformal realization in compactified D4 branes
We develop the framework of boundary derivative expansion (BDE) formalism of
fluid/gravity correspondence in compactified D4-brane system, which is a
nonconformal background used in top-down holographic QCD models. Such models
contain the D4-D6 model and the Sakai-Sugimoto (SS) model, with the background
of the compactified black D4 branes under the near horizon limit. By using the
dimensional reduction technique, we derive a 5D Einstein gravity minimally
coupled with 3 scalar fields from the 10D D4-brane background. Following the
BDE formalism of fluid/gravity correspondence in the conformal background, we
directly derive all the first order transport coefficients for nonconformal
gluonic matter. The results of the ratio of the bulk to shear viscosity and the
sound speed agree with those obtained from the Green-Kubo method. This
agreement guarantees the validity of the BDE formalism of fluid/gravity duality
in the nonconformal D-brane background, which can be used to calculate the
second order transport coefficients in nonconformal background.Comment: 25 page
Brominated Flame Retardants in Fish of Lake Geneva (Switzerland)
Polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD) were determined in fish (Salmo trutta forma lacustris) from Lake Geneva. Brominated flame retardants were detected in all nine samples with an average concentration for the sum of BDE-28, BDE-47, BDE-49, BDE-66, BDE-99, BDE-100, BDE-119, BDE-153, BDE-154 and BDE-209 of 207ng per g lipid weight (ngglw−1). The congener patterns were dominated by BDE-47. The average concentration of HBCD was 168ngglw−
Is social identity belief independent?
In this paper we aim to disentangle the effects on in-group favoritism driven by beliefs from those stemming from group identity, with the final goal of testing the relative power of three potential explanations of this bias: The Beliefs Driven Explanation (BDE), the Group Identity Explanation (GIE) and the Belief-mediated Group Identity Explanation (BGE). The BDE suggests that in-group favoritism is only driven by the desire not to let others’ expectations down. The GIE claims that people have a preference, per se, for members of their group. According to the BGE, people also have a preference for members of their group, but this is mediated by their second-order beliefs. To this aim, we built an experimental design able to produce exogenous variations in both group membership and expectations, hence providing a genuine test for the rationale of in-group bias. The results of our experiment suggest that beliefs per se are not a significant explanation of in-group favoritism and hence do not provide support to the BDE. Our experimental evidence does not provide support also to the BGE. We conclude that our experiment suggests to single out the GIE as the most powerful explanation of social identity
An assessment of chemical contaminants in the marine sediments of southwest Puerto Rico
This report summarizes the results of a characterization
of chemical contaminants in the sediments in southwest
Puerto Rico. The report is part of a project to integrate
various analytical specialties to assess linkages between
chemical contaminants and the condition of coral reefs. In this phase of the project, over 120 chemical contaminants were analyzed in sediments collected, including a number of organic (e.g., hydrocarbons), inorganic (e.g., metals), and biological (bacterial) compounds/analytes. The report also provides a preliminary analysis of the association between
sediment contaminants and coral species richness.
Overall, the levels of chemical contaminants in the study area between Guanica Bay and the town of La Parguera were fairly low. At most of the sites sampled, particularly
adjacent to the town of La Parguera, concentrations of
organic and inorganic contaminants were below the median values from NOAA’s National Status and Trends Program, which monitors the Nation’s coastal and estuarine waters for chemical contaminants. Elevated levels of a number of contaminant classes were seen at the two sites sampled within Guanica Bay.
An initial analysis of modeled PAH (hydrocarbon) data and coral species richness (reef building species) indicated a strong negative correlation between the presence of PAHs in the sediments and coral species richness. Additional work is needed to assess possible reasons for this observed pattern. (PDF contains 126 pages)
Notes on the amphipacific relations of Hawaiian Cladoniaceae
The total number of currently accepted species of Cladoniaceae in the Hawaiian Islands is 22. Several taxonomic problems still exist, however. The effects of isolation are clear among Cladoniaceae. Endemism is high (c. 40%); and, the number of species low. The species must have reached the archipelago via long-distance trans-oceanic dispersal, probably aided by the abundant production of lichen propagules, such as soredia and microsquamules. Although most of the species found in Hawaii are widely distributed, the Hawaiian Cladoniaceae show slight affinities to those of E and SE Asia. Cladonia polyphylla Mont. & v.d. Bosch is an older name for C. fruticulosa Krempelh., and is lectotypified from authentic material. C. leprosula H. Magn. is included in C. ochrochlora Flörke
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