Polarization Lidar at Summit, Greenland, for the Detection of Cloud Phase and Particle Orientation

Accurate measurements of cloud properties are necessary to document the full range of cloud conditions and characteristics. The Cloud, Aerosol Polarization and Backscatter Lidar (CAPABL) has been developed to address this need by measuring depolarization, particle orientation, and the backscatter of clouds and aerosols. The lidar is located at Summit, Greenland (72.6°N, 38.5°W; 3200 m MSL), as part of the Integrated Characterization of Energy, Clouds, Atmospheric State, and Precipitation at Summit Project and NOAA's Earth System Research Laboratory's Global Monitoring Division's lidar network. Here, the instrument is described with particular emphasis placed upon the implementation of new polarization methods developed to measure particle orientation and improve the overall accuracy of lidar depolarization measurements. Initial results from the lidar are also shown to demonstrate the ability of the lidar to observe cloud properties

Pulmonary retransplantation:Predictors of graft function and survival in 230 patients

Background. Despite improving results in lung transplantation, a significant number of grafts fail early or late postoperatively. The pulmonary retransplant registry was founded in 1991 to determine the predictors of outcome after retransplantation. We hypothesized that ambulatory status of the recipient and center retransplant volume, which had been previously shown to predict survival after retransplantation, would also be associated with improved graft function postoperatively. Methods. Two hundred thirty patients underwent retransplantation in 47 centers from 1985 to 1996. Logistic regression methods were used to determine variables associated with, and predictive of, survival and lung function after retransplantation. Results. Kaplan-Meier survival was 47% +/- 3%, 40% +/- 3%, and 33% +/- 4% at 1, 2, and 3 years, respectively. On multivariable analysis, the predictors of survival included ambulatory status or lack of ventilator support preoperatively (p = 0.005; odds ratio, 1.62; 95% confidence interval, 1.15 to 2.27), followed by retransplantation after 1991 (p = 0.048; odds ratio, 1.41; 95% confidence interval, 1.003 to 1.99). Ambulatory, nonventilated patients undergoing retransplantation after 1991 had a 1-year survival of 64% +/- 5% versus 33% +/- 4% for nonambulatory, ventilated recipients. Eighty-one percent, 70%, 62%, and 56% of survivors were free of bronchiolitis obliterans syndrome at 1, 2, 3, and 4 years after retransplantation, respectively. Factors associated with freedom from stage 3 (severe) bronchiolitis obliterans syndrome at 2 years after retransplantation included an interval between transplants greater than 2 years (p = 0.01), the lack of ventilatory support before retransplantation (p = 0.03), increasing retransplant experience within each center (fifth and higher retransplant patient, p = 0.04), and total center volume of five or more retransplant operations (P = 0.05). Conclusions. Nonambulatory, ventilated patients should not be considered for retransplantation with the same priority as other candidates. The best intermediate-term functional results occurred in more experienced centers, in nonventilated patients, and in patients undergoing retransplantation more than 2 years after their first transplant. In view of the scarcity of lung donors, patient selection for retransplantation should remain strict and should be guided by the outcome data reviewed in this article. (C) 1998 by The Society of Thoracic Surgeons