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61.
Atmospheric transport of polybrominated diphenyl ethers and polychlorinated biphenyls to the Baltic Sea 总被引:5,自引:0,他引:5
The atmospheric transport of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) was compared by measuring concentrations in air and deposition on an island located in the central basin of the Baltic Sea. Median sigmaPBDE and sigmaPCB concentrations (gaseous + particle) were 8.6 and 7.4 pg m(-3), respectively. Airborne PCBs were mainly found in the gaseous phase, while most of the PBDEs were detected on particles, which agrees with predicted particle/gas distributions. SigmaPBDE levels were dominated by the decabrominated BDE209 followed bythe tetrabrominated BDE47 and pentabrominated BDE99. BDE209 is a marker for the environmental distribution of the commercial deca-BDE formulation (>99.5% BDE209), whereas BDE47 and BDE99 are markers for the commercial penta-BDE mixture. General correlations between PBDEs and PCBs suggested similarities in sources and transport mechanism, while more detailed examination of the data identified notable behaviors and exceptions. Differences in regression slopes among tetra-, penta-, and decabrominated PBDEs may reflect different transport processes and the change in usage pattern. Tetra- and pentabrominated PBDEs may originate from secondary sources such as air surface exchange in a manner similar to that of the PCBs, while the deca-BDE209 formulation still has primary sources. The tribrominated BDE17 was also detected and is proposed to be a breakdown product due to atmospheric debromination processes. PBDEs had higher washout ratios than PCBs, explaining their higher concentrations compared to PCBs in precipitation (median of 6.0 and 0.5 ng L(-1) for sigmaBDE and sigmaPCB concentrations ("dissolved" + particle), respectively) than in air. The calculated yearly deposition of PBDEs and PCBs indicated that the atmospheric input of PBDEs to the Baltic Proper is currently exceeding that of the PCBs by a factor of 40, while that of the PCBs is decreasing. 相似文献
62.
Recent developments in the field of process engineering and manufacturing sciences enable a new level of process understanding. However, extracting this understanding from increasing amounts of information is challenging. The aim of this study was to create a process vector from a model process describing all relevant information and, by that means, create a tool for combining and visualizing this information. Physical (impeller torque and temperature) and chemical (near-infrared spectroscopy) information from a small-scale high-shear granulation was used in the process vector. The vectors created were visualized by two different methods: principal component analysis (PCA) and the self-organizing map (SOM). None of the individual measurement techniques were able to describe the state of the process alone, although they provided important information about the process. By combining the data and visualizing it, an overview could be achieved. The SOM approach had two advantages over the PCA: it presented the results in terms of the original variables and enabled the analysis of nonlinear responses. However, both visualization methods could be used to describe the progress of the process and to increase the level of process understanding. 相似文献
63.
Two studies, using a total of 109 undergraduates as Ss, tested the validity of the bogus pipeline procedure for eliciting truthful responses from Ss in social psychological experiments. Ss were illegitimately informed about how to perform well on an experimental test, were tested, and then were asked whether they had possessed this prior information. As compared to Ss responding to pencil-and-paper questions for face-to-face questioning by the experimenter, those in a bogus pipeline condition confessed more often. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
64.
Lilienthal ND Alsafar H Conerty J Fernandez R Kong C Smith DK 《Analytical chemistry》2003,75(14):3322-3328
Electrodes modified with Nafion films containing 2,7-dimethyldiazapyrenium (DAP2+) were prepared and characterized with voltammetry by themselves and in the presence of organic substrates. The large, planar, electron-poor aromatic surface in DAP2+ facilitates pi-stacking interactions with other planar aromatic molecules, particularly those that are negatively charged or electron-rich. Previous studies showed that the reduction of DAP2+ decreases the strength of these interactions, making the binding redox-dependent, and resulting in negative shifts in the E(1/2) of DAP2+/+. This study shows that the redox-dependent binding ability of DAP2+ is retained in Nafion, but the selectivity is considerably different. Most significantly, the electron-rich, neutral aromatic compounds that produced small shifts in the E(1/2) of DAP2+/+ in solution cause much larger shifts, up to -110 mV, with the modified electrodes. With indole as a substrate, Nernstian behavior is observed (-60 mV shift per log[indole]) between 10 and 0.5 mM. 相似文献
65.
The widespread implementation of systems of care represents an important opportunity to integrate behavioral, cognitive, milieu, client-centered, group, solution-focused, systems, multicultural, and ecological approaches to child and family therapy. This integrated approach is described and illustrated, and systems of care principles are considered to be a useful foundation for effective therapeutic practices for difficult problems of children, families, and adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
66.
Facing the scale, heterogeneity and dynamics of the global computing platform emerging on top of the Internet, autonomic computing has been raised recently as one of the top challenges of computer science research. Such a paradigm calls for alternative programming abstractions, able to express autonomic behaviours. In this quest, nature-inspired analogies regained a lot of interest. More specifically, the chemical programming paradigm, which envisions a program’s execution as a succession of reactions between molecules representing data to produce a result, has been shown to provide some adequate abstractions for the high-level specification of autonomic systems. 相似文献
67.
68.
Elen Cristina Pradella Balloni Flávia Lucisano Botelho do Amaral Fabiana Mantovani Gomes França Cecilia Pedroso Turssi 《Journal of Adhesion Science and Technology》2013,27(10):1133-1141
This study evaluated the effect of chlorhexidine (CLX) in cavities prepared with either ultrasound-mounted CVDentUS diamond tips or conventional diamond burs on dentin bond strength after 24 h and 180 days. Forty-eight dentin surfaces from sound third molars were flattened and divided into four groups (n = 12), according to the type of cavity preparation (CVDentUS ultrasound tip or conventional diamond) and with or without 2% CLX (Consepsis) treatment. After application of the adhesive system (Clearfil SE Bond), microhybrid composite resin blocks (Charisma) were made on the dentin surface in increments. After 24 h, the specimens were sectioned into stick-shaped samples with an adhesive interface of approximately 1 mm2. From each tooth, half of the sticks were evaluated after 24 h of storage in distilled water and the other half after 180 days, using a universal testing machine. Three-way analysis of variance showed no significant triple interactions (p = 0.722) or double interactions between factors. Higher bond strength values were observed with the use of ultrasonic tips (p = 0.019), irrespective of whether or not CLX was applied in either time period. No difference in bond strength values was observed in terms of CLX application (p = 0.581). No significant difference in bond strength values was shown after storage for 24 h or 180 days (p = 0.302). In conclusion, the ultrasonic tips promoted greater bond strength to dentin, irrespective of whether or not CLX was applied, and storage time. 相似文献
69.
70.
Quigley Brian M.; Corbett Amy B.; Tedeschi James T. 《Canadian Metallurgical Quarterly》2002,16(4):318
Three hundred thirty-nine college students were surveyed regarding their usual drinking behavior, alcohol expectancies, desired identity of power, and experience with alcohol-related violence. Eight percent indicated having been in a fight in a bar, and 16% indicated having been in a fight while drinking in the previous year. Male heavy drinkers were more likely than female heavy drinkers to experience alcohol-related and bar violence. The belief that intoxication causes one to become aggressive was related to experiencing alcohol-related violence. However, the relationship of alcohol expectancies to alcohol-related aggression was moderated by an individual difference in the desire to be seen as powerful. Results are discussed in terms of cognitive models of alcohol expectancy development and maintenance. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献