Searching for Gravitational Waves from Cosmological Phase Transitions with the NANOGrav 12.5-Year Dataset.

We search for a first-order phase transition gravitational wave signal in 45 pulsars from the NANOGrav 12.5-year dataset. We find that the data can be modeled in terms of a strong first order phase transition taking place at temperatures below the electroweak scale. However, we do not observe any strong preference for a phase-transition interpretation of the signal over the standard astrophysical interpretation in terms of supermassive black hole mergers; but we expect to gain additional discriminating power with future datasets, improving the signal to noise ratio and extending the sensitivity window to lower frequencies. An interesting open question is how well gravitational wave observatories could separate such signals.

Management of infected femoral closure devices.

An increase in infectious complications has been noted with the introduction of percutaneous femoral artery closure devices. We report five cases of infected groins and/or femoral arteries following angiographic procedures that were completed using the Perclose Suture Mediated Closure Device (Perclose). Each patient required drainage of the abscess and removal of the Perclose suture. Most patients required more extensive vascular reconstructive procedures. When these complications arise, we recommend expeditious drainage of the abscess, removal of the suture, and adequate exposure of the femoral artery to facilitate repair of the vessel.