A critique of general allometry-inspired models for estimating forest carbon density from airborne LiDAR.

There is currently much interest in developing general approaches for mapping forest aboveground carbon density using structural information contained in airborne LiDAR data. The most widely utilized model in tropical forests assumes that aboveground carbon density is a compound power function of top of canopy height (a metric easily derived from LiDAR), basal area and wood density. Here we derive the model in terms of the geometry of individual tree crowns within forest stands, showing how scaling exponents in the aboveground carbon density model arise from the height-diameter (H-D) and projected crown area-diameter (C-D) allometries of individual trees.

Are urgent care centers a viable venue for recruitment in clinical trials?

Clinical trials are extremely difficult to undertake and recruiting patients for these trials is one of the most significant challenges. This brief report sought to determine the suitability of an urgent care center as a research recruitment site by assessing its patients' views on participating in clinical trials. One thousand and two subjects were surveyed over a 45-day period; 9.