Epinephrine-induced conditioned taste aversion

The ability of the hormone epinephrine to induce a conditioned taste aversion was investigated in three experiments. Aversions induced by epinephrine appear more easily conditioned to a highly preferred sucrose solution than to a less preferred sucrose/saline solution. A dose-response curve also exists; better conditioning is evident following injection of either 0.3 or 0.5 mg/kg epinephrine than it is following a 0.1 mg/kg dose. A arcadian rhythmicity also occurs for epinephrine-induced sucrose aversions. When the endogenous levels of this hormone are at trough, conditioning is greater than when they are elevated. This circadian pattern is interpreted with respect to the degree of discriminability between endogenous and exogenous epinephrine levels.     

The conditioned reconstructed process

We investigate a neutral model for speciation and extinction, the constant rate birth-death process. The process is conditioned to have n extant species today, we look at the tree distribution of the reconstructed trees—i.e. the trees without the extinct species. Whereas the tree shape distribution is well-known and actually the same as under the pure birth process, no analytic results for the speciation times were known. We provide the distribution for the speciation times and calculate the expectations analytically. This characterizes the reconstructed trees completely. We will show how the results can be used to date phylogenies.