Tracer release experiments results

Figure 3 Some horizontal mixing estimates as a function of space scale. Results are from a small-scale float deployment (triangles, Stommel, 1949), the tracer release experiment (squares, Ledwell et al., 1998), and some larger-scale advection-diffusion balances (circles, see later sections) and estimates from radium isotopes (diamonds,...

During pre-operational SILAM evaluation its results were compared with the data of the European Tracer Experiment (Sofiev et al. 2006b), Chernobyl and Algeciras accidental releases. For AQ related species, the system output was compared with the European AQ networks for the period of 2000-2002 and several campaigns and for some extreme episodes, such as the case of wild-land fires during spring and summer 2006. 

This discussion would not be complete without mention of the purposeful tracer experiment carried out as a component of WOCE, using SFg released in the open ocean. The results confirmed the earlier estimates of very low diapycnal diffusivity, of the order of O.lcm s, implying that heat, salt, and tracers must penetrate the thermocline primary by transport along, rather than across, density surfaces. 

The tracer, C-radopride binds to D2-DA receptors. Decreased accumulation of the tracer results from the release of endogenous DA that competes for binding with the tracer. Jon-Kar Zubieta and colleagues at the University of Michigan showed that the extent to which a person responds to placebos corrdates with DA release in the nudeus accumbens. These persons who responded to placebos had more DA-related neuronal activity in their left nucleus accumbens than other volunteers (Neuron, July 19,2007). DA release in the nucleus accumbens is involved not only in the ability to experience pleasure and reward, but also related to the "high caused by illicit drugs. DA release is increased when the person anticipates pleasure. 

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