The presence of other complicating diseases also reduces the likelihood of a favourable outcome. Paraplegia complicating thoracotomy is rare but catastrophic. Additional precautions were not needed for blood-borne infections, unless there were complicating factors. Landowner interests are a further complicating factor. The entry of several states into the Union has been delayed due to complicating factors. These programs have also been criticised for complicating courtship with needless public expectation. Complicating factors include safety, durability, thermal breakdown and cost. Synergistic responses are a complicating factor in environmental modeling. Plus disease can be present as a major complicating factor at any stage. One complicating factor is that the water level can vary dramatically. Further complicating the situation, potholes in the Kuito airport strip slowed aid deliveries. Further complicating domestic matters was the matter of the succession. Further complicating this picture are repetition patterns. Another complicating factor is the use of burst transfers. Another complicating factor is the different track gauges in use.