Die Value-Shift-Erklärung im Attraktionseffekt

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Akzeptanz und Nutzung des E-Commerce im B2C: Eine empirische Analyse

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Trittbrettfahren bei Sportevents: das Ambush-Marketing

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Sponsoring und Ambushing: Eine verhaltenswissenschaftliche Analyse

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Modelling iodide – iodate speciation in atmospheric aerosol: Contributions of inorganic and organic iodine chemistry

The speciation of iodine in atmospheric aerosol is currently poorly understood. Models predict negligible iodide concentrations but accumulation of iodate in aerosol, both of which is not confirmed by recent measurements. We present an updated aqueous phase iodine chemistry scheme for use in atmospheric chemistry models and discuss sensitivity studies with the marine boundary layer model MISTRA. These studies show that iodate can be reduced in acidic aerosol by inorganic reactions, i.e., iodate does not necessarily accumulate in particles. Furthermore, the transformation of particulate iodide to volatile iodine species likely has been overestimated in previous model studies due to negligence of collision-induced upper limits for the reaction rates. However, inorganic reaction cycles still do not seem to be sufficient to reproduce the observed range of iodide – iodate speciation in atmospheric aerosol. Therefore, we also investigate the effects of the recently suggested reaction of HOI with dissolved organic matter to produce iodide. If this reaction is fast enough to compete with the inorganic mechanism, it would not only directly lead to enhanced iodide concentrations but, indirectly via speed-up of the inorganic iodate reduction cycles, also to a decrease in iodate concentrations. Hence, according to our model studies, organic iodine chemistry, combined with inorganic reaction cycles, is able to reproduce observations. The presented chemistry cycles are highly dependent on pH and thus offer an explanation for the large observed variability of the iodide – iodate speciation in atmospheric aerosol

Modeling iodide ? iodate speciation in atmospheric aerosol

International audienceThe speciation of iodine in atmospheric aerosol is currently poorly understood. Models predict negligible iodide concentrations and accumulation of iodate in aerosol, both of which is not confirmed by recent measurements. We present an updated aqueous phase iodine chemistry scheme for use in atmospheric chemistry models and discuss sensitivity studies with the marine boundary layer model MISTRA. These studies show that iodate can be reduced in acidic aerosol by inorganic reactions, i.e., iodate does not necessarily accumulate in particles. Furthermore, the transformation of particulate iodide to volatile iodine species likely has been overestimated in previous model studies due to negligence of collision-induced upper limits for the reaction rates. However, inorganic reaction cycles still do not seem to be sufficient to reproduce the observed range of iodide ? iodate speciation in atmospheric aerosol. Therefore, we also investigate the effects of the recently suggested reaction of HOI with dissolved organic matter to produce iodide. If this reaction is fast enough to compete with the inorganic mechanism, it would not only directly lead to enhanced iodide concentrations but, indirectly via speed-up of the inorganic iodate reduction cycles, also to a decrease in iodate concentrations. Hence, according to our model studies, organic iodine chemistry, combined with inorganic reaction cycles, is able to reproduce observations. The presented chemistry cycles are highly dependent on pH and thus offer an explanation for the large observed variability of the iodide ? iodate speciation in atmospheric aerosol

Effects of 3-nitrooxypropanol on feeding behavior and rumen fermentation in beef cattle fed a growing diet

First Place at Spring 3-Minute Thesis CompetitionSecond Place at the Denman Undergraduate Research ForumThird Place at the CFAES Undergraduate Research ForumMitigating enteric methane production from ruminants is critical for sustainable livestock operations. Three-nitrooxypropanol (NOP) is an effective feed additive for mitigating enteric methane production in beef cattle. However, feeding NOP to beef cattle often decreases feed intake and alters feed fermentation in the rumen. Therefore, the objective of the study was to determine whether changes in feed intake and rumen fermentation are caused by changes in feeding behavior when supplementing a growing diet with NOP. The experiment used 9 ruminally-cannulated beef steers in a repeated 3 × 3 Latin square design. Steers received one of the three following treatments: a control diet (CON); the CON diet supplemented with NOP (dNOP; 1g NOP per cow d-1); or the CON diet with an infusion of NOP into the rumen (NOPinf; 1g NOP per cow d-1). The CON diet was a typical high forage diet that is fed to growing beef cattle in the US. Rumen content was collected via cannula to examine rumen fermentation. Methane production of individual animals was measured using the Greenfeed system. To observe animal behaviors, cameras were installed to continuously record individual steers for 48 hours. Total duration and frequency of feeding, drinking, activity, and oral manipulation behaviors were collected. Meal time (min/d) and frequency of individual animals were calculated from feeding behavior. Rumen samples were collected via rumen cannula to determine rumen fermentation characteristics (i.e., pH, volatile fatty acid concentration, as well as lactate concentration. Data were analyzed using an analysis of variance model using the repeated measures Mixed Procedure of SAS (SAS Inst. Inc., Cary, NC). Feeding NOP decreased enteric methane production by approximately 18% compared with CON. Rumen fermentation was altered by NOP as expected (i.e., rumen pH and proportion of short chain fatty acids). However, there were no significant differences in feeding, drinking, or activity behaviors between treatments since total duration and frequency of oral manipulation behaviors (chain chewing, biting, and licking) were lower (P < 0.03) for dNOP and NOPinf compared to CON. According to the results, NOP changed rumen fermentation, but the changes were not caused by a change in feeding behaviors in beef cattle fed a growing diet.Animal Science Undergraduate Research Experience (ASURE) ProgramDSM Nutritional ProductsNo embargoAcademic Major: Animal Science

Climate sensitivity of radiative impacts from transport systems

Comparing individual components of a total climate impact is traditionally done in terms of radiative forcing. However, the climate impact of transport systems includes contributions that are likely to imply climate sensitivity parameters distinctly different from the “reference value” for a homogeneous CO2 perturbation. We propose to introduce efficacy factors for each component into the assessment. The way of proceeding is illustrated using aviation as an example, and prospects for evaluating the other transport system in the EU project QUANTIFY are given