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Variability in transplant access exists, but barriers to referral and evaluation are underexplored due to lack of national surveillance data. We examined referral for kidney transplantation evaluation and start of the evaluation among 34 857 incident, adult (18-79 years) end-stage kidney disease patients from 690 dialysis facilities in the United States Renal Data System from January 1, 2012 through August 31, 2016, followed through February 2018 and linked data to referral and evaluation data from nine transplant centers in Georgia, North Carolina, and South Carolina. Multivariable-adjusted competing risk analysis examined each outcome. The median within-facility cumulative percentage of patients referred for kidney transplantation within 1 year of dialysis at the 690 dialysis facilities in Network 6 was 33.7% (interquartile range [IQR]: 25.3%-43.1%). Only 48.3% of referred patients started the transplant evaluation within 6 months of referral. In multivariable analyses, factors associated with referral vs evaluation start among those referred at any time differed. For example, black, non-Hispanic patients had a higher rate of referral (hazard ratio [HR]: 1.22; 95% confidence interval [CI]: 1.18-1.27), but lower evaluation start among those referred (HR: 0.93; 95% CI: 0.88-0.98), vs white non-Hispanic patients. Barriers to transplant varied by step, and national surveillance data should be collected on early transplant steps to improve transplant access.

The rapid and accurate extraction of water information from satellite imagery has been a crucial topic in remote sensing applications and has important value in water resources management, water environment monitoring, and disaster emergency management. Although the OLI-2 sensor onboard Landsat-9 is similar to the well-known OLI onboard Landsat-8, there were significant differences in the average absolute percentage change in the bands for water detection. Additionally, the performance of Landsat-9 in water body extraction is yet to be fully understood. Therefore, it is crucial to conduct comparative studies to evaluate the water extraction performance of Landsat-9 with Landsat-8. In this study, we analyze the performance of simultaneous Landsat-8 and Landsat-9 data for water body extraction based on eight common water indices (Normalized Difference Water Index (NDWI) and Modified Normalized Difference Water Index (MNDWI), Augmented Normalized Difference Water Index (ANDWI), Water Index 2015 (WI2015), tasseled cap wetness index (TCW), Automated Water Extraction Index for scenes with shadows (AWEIsh) and without shadows (AWEInsh) and Multi-Band Water Index (MBWI)) to extract water bodies in seven study sites worldwide. The Otsu algorithm is utilized to automatically determine the optimal segmentation threshold for water body extraction. The results showed that (1) Landsat-9 satellite data can be used for water body extraction effectively, with results consistent with those from Landsat-8. The eight selected water indices in this study are applicable to both Landsat-8 and Landsat-9 satellites. (2) The NDWI index shows a larger variability in accuracy compared to other indices when used on Landsat-8 and Landsat-9 imagery. Therefore, additional caution should be exercised when using the NDWI for water body analysis with both Landsat-8 and Landsat-9 satellites simultaneously. (3) For Landsat-8 and Landsat-9 imagery, ratio-based water indices tend to have more omission errors, while difference-based indices are more prone to commission errors. Overall, ratio-based indices exhibit greater variability in overall accuracy, whereas difference-based indices demonstrate lower sensitivity to variations in the study area, showing smaller overall accuracy fluctuations and higher robustness. This study can provide necessary references for the selection of water indices based on the newest Landsat-9 data. The results are crucial for guiding the combined use of Landsat-8 and Landsat-9 for global surface water mapping and understanding its long-term changes. [ABSTRACT FROM AUTHOR]

Abstract: We present a comparative tectonic analysis of the North China Craton (NCC), which has lost parts of its root, with the Yilgarn and Superior cratons, which preserve their roots. [...]