"In practice" limitations are extremely important for evaluating current claims and improving future research (for example see Kate Button on statistical power, Alok Jha on fraud and misconduct and Ed Yong on replication studies), but tell us nothing about the "in principle" limits of neuroscience.
Those areas are off-limits, in principle.
ZFRs, like ZFNs, have the potential to target many new sequences, being limited in principle only by the range of sequences for which specific zinc finger domains can be made and by the sequence selectivity of the catalytic domain [1].
The quantity of phenol produced by this mechanism is limited in principle once all the STS activity has been inactivated.[ 46] However, degradation of the sulfamate following prolonged circulation in plasma might provide an additional route for the formation of the phenol.
But there are problems with term limits, both in principle and in practice.
These physical performance limits could, in principle, be achieved with either a feedback or a feedforward control strategy.
The elastic limit is in principle different from the proportional limit, which marks the end of the kind of elastic behaviour that can be described by Hooke's law, namely, that in which the stress is proportional to the strain (relative deformation) or equivalently that in which the load is proportional to the displacement.
Due to the variety of external conditions, cellular contexts and experimental systems the limiting step in principle can be any in the sequence of events in protein translation, hence, this or that microRNA mechanism can become dominant in a concrete environment.
Obama embraced both constitutional and international legal limits, at least in principle, even as he struggled to define them in practice.
