Emphasise short run

Author: pgleeson

README.md

@@ -27,7 +27,7 @@ We have put together a [Docker container](https://hub.docker.com/r/openworm/open
 
 <img src="https://raw.githubusercontent.com/openworm/OpenWorm/master/img/muscle-activity.png" width="250"><img src="https://raw.githubusercontent.com/openworm/OpenWorm/master/img/neuron-activity.png" width="350">
 
-**NOTE**: Running the simulation for the full amount of time would produce content like the above.  However, in order to run in a reasonable amount of time, the default run time for the simulation is limited.  As such, you will see only a partial output, equivalent to about 5% of run time, compared to the examples above.  To extend the run time, use the `-d` argument as described below.
+**NOTE**: Running the simulation for the full amount of time would produce content like the above.  However, in order to run in a reasonable amount of time, **the default run time for the simulation is limited**.  As such, you will see only a partial output, equivalent to about 5% of run time, compared to the examples above.  To extend the run time, use the `-d` argument as described below.
 
 **Installation**