Sub-percent Photometry: Faint DA White Dwarf Spectophotometric Standards for Astrophysical Observatories

We have established a network of 19 faint (16.5 mag $< V <$19 mag) northern and equatorial DA white dwarfs as spectrophotometric standards for present and future wide-field observatories. Our analysis infers SED models for the stars that are tied to the three CALSPEC primary standards. Our SED models are consistent with panchromatic Hubble Space Telescope ($HST$) photometry to better than 1%. The excellent agreement between observations and models validates the use of non-local-thermodynamic-equilibrium (NLTE) DA white dwarf atmospheres extinguished by interstellar dust as accurate spectrophotometric references. Our standards are accessible from both hemispheres and suitable for ground and space-based observatories covering the ultraviolet to the near infrared. The high-precision of these faint sources make our network of standards ideally suited for any experiment that has very stringent requirements on flux calibration, such as studies of dark energy using the Large Synoptic Survey Telescope (LSST) and the Wide-Field Infrared Survey Telescope ($WFIRST$).Comment: 46 pages, 23 figures, 8 tables, accepted for publication in ApJ

Robotically Assisted Mitral Valve Repair—Port-Only Totally Endoscopic Approach

Robotic mitral valve repair (MVR) is an emerging option to treat degenerative valve disease. Compared to open thoracotomy, robotic mitral valve surgery has been shown to afford decreased postoperative length of stay with comparable rates of mortality and morbidity. Among the variety of techniques for robotic MVR, the totally endoscopic approach remains the least invasive method to date. In this report, we describe our technique for totally endoscopic robotically-assisted MVR. In particular, we seek to highlight the use of several unique techniques in MVR. Percutaneous cannulation with use of the endoballoon is employed for cardiopulmonary bypass (CPB), thus avoiding traditional aortic cross-clamping. Moreover, intercostal nerve cryoanesthesia is performed from T3–T9 to reduce post-operative pain and aid in reducing opioid management. Barbed, nonabsorbable sutures are used throughout the procedure (for left atrial appendage closure, mitral valve annuloplasty band placement, left atrial closure, pericardial re-approximation), eliminating the need for knot-tying at several steps. We also detail the installation of two sets of neochords for mitral regurgitation and the fastening of the mitral annuloplasty band. Finally, we would like to highlight the small size of each port used in the case (eight millimeters maximum diameter). Taken together, these features of the robotic platform make it notable for its minimally invasive approach to MVR

Improving quality of care through early discharge on postoperative day one or two following robotic cardiac surgery

Cardiac surgery is traditionally associated with a postoperative length of stay (LOS) of at least one week.1-2. The reduced invasiveness of the robotic platform facilitates discharge on postoperative day one (POD1) or two (POD2), thus minimizing cost and risk of hospital-associated complications. We sought to evaluate the characteristics of patients who underwent POD1 or POD2 discharge after robotic cardiac surgery at Jefferson