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Water colour remote sensing is a valuable tool for assessing bio-optical and biogeochemical parameters across the vast extent of the Amazon River Continuum (ARC). However, accurate retrieval depends on selecting the best atmospheric correction (AC). Four AC processors (Acolite, Polymer, C2RCC, OC-SMART) were evaluated against in situ remote sensing reflectance (Rrs) measurements. K-means classification identified four optical water types (OWTs) that are affected by the ARC. Two OWTs showed seasonal differences in the Lower Amazon River, influenced by the increase in suspended sediment concentration with river discharge. The other OWTs in the Amazon River Plume are dominated by phytoplankton or by a mixture of optically significant constituents. The Quality Water Index Polynomial method used to assess the quality of in situ and orbital Rrs had a high failure rate when the Apparent Visible Wavelength was >580 nm for in situ Rrs. OC-SMART Rrs products showed better spectral quality compared to Rrs derived from other AC processors evaluated in this study. These results improve our understanding of remotely sensing very turbid waters, such as those in the Amazon River Continuum.

Abstract Background Conventional echocardiographic technique for assessment of volume status and cardiac contractility utilizes left ventricular end-diastolic area (LVEDA) and fractional area of change (FAC), respectively. Our goal was to find a technically reliable yet faster technique to evaluate volume status and contractility by measuring left ventricular end-diastolic diameter (LVEDD) and fractional shortening (FS) in a cohort of mechanically ventilated trauma and burn patients using hemodynamic transesophageal echocardiographic (hTEE) monitoring. Methods Retrospective chart review performed at trauma/burn intensive care unit (TBICU). Data on 88 mechanically ventilated surgical intensive care patients cared for between July 2013 and July 2015 were reviewed. Initial measurements of LVEDA, left ventricular end-systolic area (LVESA) and FAC were collected. Post-processing left ventricular end-systolic (LVESD) and end-diastolic diameters (LVEDD) were measured and fractional shortening (FS) was calculated. Two orthogonal measurements of LV diameter were obtained in transverse (Tr) and posteroanterior (PA) orientation. Results There was a significant correlation between transverse and posteroanterior left ventricular diameter measurements in both systole and diastole. In systole, r = 0.92, p