The gold standard of making compelling causal inferences depends on experimental designs in which the assignment of participants to treatments is "exogenous" rather than "endogenous".
In the case where changes in the mental stream occasion in the absence of any sensory stimulus, these are said to be the result of unconscious traces of past experience rather than endogenous to mind itself.
The appearance of clade F in Oregon, as well as the clade C isolate in Colorado, may represent introduced, rather than endogenous, virus.
Vector-borne disease models have with rare exception [35], [36], [37] assumed that vectors die at a constant rate based on the biological assumption that mosquitoes die of exogenous causes (swatting, predation, disease, weather) rather than endogenous causes (old age).
This assumption is less empirically-supportable, and these changes may be more appropriately seen as exogenous rather than endogenous (e.g. there is no sense in which the printing press resulted from mathematical knowledge of the 15th century).
Importantly, wild type C57Bl/6 mice administered GW501516 did not exhibit these changes (table S1), but did show the expected upregulation of genes involved in lipid metabolism (table S5), thereby confirming that the observed induction of IL1-signalling was triggered by the transgene rather than endogenous murine PPARβ/δ.
It is noteworthy that specific patterns of bioluminescence signals in the embryo do not represent distribution of the mRNA, but rather real endogenous BMP signals because the same embryo including the Venus mRNA showed almost ubiquitous expression patterns among all cells over time.
Also, thymidylate synthase should be blocked to enhance incorporation of the label rather than endogenous thymidylate.
However, this effect is only observed with pharmacological amounts of 15d-PGJ2 rathan than endogenous concentrations.
The high room air levels and the observed emission by bloodlines render the aforementioned species pollutants rather than endogenous compounds.
