On a Problem of Burnside

Burnside posed the question as to whether or not there exist groups having an external automorphism that behaves in a certain, specific way like an inner automorphism: we shall define such automorphisms to be nearly-inner. NI-groups are fairly rare. With the aid of the computer algebra system Magma - in particular with the aid of its small group database - we set out to test this hypothesis.

Automated Portal Placement for Arthroscopic Hip Surgery

Placing portal incisions during arthroscopic hip surgery presents challenges for surgeons in terms of anatomic accessibility and patient safety. Based on key anatomic landmarks and portal placement information from recent literature, suggested portal incisions were determined. Guidance in the placement of the three most common portal incision locations (anterior, anterolateral, and posterolateral) for arthroscopic surgery; in addition to visual feedback on tool trajectory to the hip joint is provided in real time by a computer aided system for hip arthroscopy. By simplifying the portal placement process, one of the most challenging aspects of arthroscopic hip surgery, an increased use of this minimally invasive technique could be possible. In addition to portal information, improvements to an existing computer aided system for arthroscopic hip surgery, including a new hip model and redesigned mechanical tracking linkage, were completed.